Two 500-year floods in 15 years

By: Dr. Jeff Masters , 2:48 PM GMT on June 19, 2008

The U.S. Geological Survey has preliminary data showing that this month's floods on four of Iowa's rivers--the Cedar, Iowa, Shell Rock, and Wapsipinicon--were 500-year floods. Back in 1993, many rivers in the Midwest also experienced 500-year floods, so the region has endured two 500-year floods in the past 15 years. How can this be? First of all a definition--a 500-year flood is an event that has only a 0.2% chance of occurring in a given year, based on available river flow data. Of course, reliable data only goes back a century at most, so designation of a 500-year flood event is somewhat subjective. Still, it seems rather improbable that two such huge floods should occur within such a short time span, raising the question of whether the floods were, in part, human-caused.

In a provocative story in the Washington Post today, it was pointed out that part of the flooding is due to the draining of wetlands for farming purposes. As nature's natural buffers against flooding are drained and filled to provide room for more farmland, run-off and flooding are bound to increase. Furthermore, as more levees are built to protect more valuable farmland and new developments, flood waters are pushed out of the former areas they were allowed to spread out in and forced into river channels behind the new levees. Even higher levees must then be constructed to hold back the increased volume of water they are asked to contain.

Climate change contributing to flooding?
The heaviest types of rains--those likely to cause flooding--have increased in recent years (see my February blog, "The future of flooding", for more detail). According to the United Nations' Intergovernmental Panel on Climate Change (IPCC) 2007 report, "The frequency of heavy precipitation events has increased over most land areas". Indeed, global warming theory has long predicted an increase in heavy precipitation events. As the climate warms, evaporation of moisture from the oceans increases, resulting in more water vapor in the air. According to the 2007 IPCC report, water vapor in the global atmosphere has increased by about 5% over the 20th century, and 4% since 1970.

Over the U.S., where we have very good precipitation records, annual average precipitation has increased 7% over the past century (Groisman et al., 2004). The same study also found a 14% increase in heavy (top 5%) and 20% increase in very heavy (top 1%) precipitation events over the U.S. in the past century. Kunkel et al. (2003) also found an increase in heavy precipitation events over the U.S. in recent decades, but noted that heavy precipitation events were nearly as frequent at the end of the 19th century and beginning of the 20th century, though the data is not as reliable back then. Thus, climate change is likely partly to blame for increased flooding in the U.S., although we cannot rule out long-term natural variations in precipitation.

Figure 1. Forecast change in precipitation and runoff for the period 2080 to 2099 compared to 1980 to 1999. The forecasts come from the A1B scenario from multiple climate models used for the Intergovernmental Panel on Climate Change (IPCC) 2007 report.

The forecast
According to a multi-model consensus of the climate models run for the Intergovernmental Panel on Climate Change (IPCC) 2007 report, precipitation and river runoff for the Mississippi River drainage basin are expected to increase only slightly by the end of this century (Figure 1). However, more of this rain is expected to fall in heavy precipitation events, the ones most likely to cause flooding. As a result, the U.S. needs to prepare for an increase in the number and severity of 100-year and 500-year flooding events in the coming century.

Kunkel, K. E., D. R. Easterling, K. Redmond, and K. Hubbard, 2003, "Temporal variations of extreme precipitation events in the United States: 1895.2000", Geophys. Res. Lett., 30(17), 1900, doi:10.1029/2003GL018052.

Groisman, P.Y., R.W. Knight, T.R. Karl, D.R. Easterling, B. Sun, and J.H. Lawrimore, 2004, "Contemporary Changes of the Hydrological Cycle over the Contiguous United States: Trends Derived from In Situ Observations," J. Hydrometeor., 5, 64.85.

It's quiet in the tropics. There are no threat areas to discuss, and none of the models are forecasting tropical storm formation in the next seven days.

Jeff Masters

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1654. cantstopthinking
12:09 AM GMT on June 25, 2008

dammit! I hate a mis-type correction North America wouldn’t have looked as it does today is what I was trying to say.
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1653. cantstopthinking
11:57 PM GMT on June 24, 2008
LMAO, GUYGEE, I guess you believe all this global warming crap too. Wow, I would have to believe your position 35 years ago was exactly opposite ( If you were still alive),since most scientist felt we were heading for a new ice age. "The number and frequency of forest fires and insect outbreaks are increasing in the interior West, the Southwest, and Alaska. Precipitation, streamflow, and stream temperatures are increasing in most of the continental United States. The western United States is experiencing reduced snowpack and earlier peaks in spring runoff. The growth of many crops and weeds is being stimulated. Migration of plant and animal species is changing the composition and structure of arid, polar, aquatic, coastal, and other ecosystems". LMAO again, guess what you morons the planet changes, and a few hundred million years ago North America didn’t would have been unrecognizable due to continental shift. Oh ya, Mount Everest grows about 5mm a year, this is directly due to all the environmentalists blowing hot air into the planet causing the mountains to grow to the point of a cataclysmic explosion one day.
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1652. guygee
2:24 PM GMT on June 23, 2008
In keeping with this blog's subject:

U.S. Department of Agriculture (USDA) Report, Synthesis and Assessment Product 4.3,

The Effects of Climate Change on Agriculture, Land Resources, Water Resources, and Biodiversity

"The U.S. Climate Change Science Program report "Synthesis and Assessment Product 4.3 (SAP 4.3): The Effects of Climate Change on Agriculture, Land Resources, Water Resources, and Biodiversity in the United States" integrates the Federal research efforts of 13 agencies on climate and global change.

The report has 38 authors from the universities, national laboratories, non-governmental organizations, and Federal service. SAP 4.3 has undergone expert peer review by 14 scientists through a Federal Advisory Committee formed by the USDA, and includes over 1,000 references. USDA was the lead agency for this report as part of its commitment to CCSP.

The report focuses on the next 25 to 50 years, and finds that climate change is already affecting U.S. water resources, agriculture, land resources, and biodiversity, and will continue to do so."

"USDA is using the report's findings in the development of a new Strategic Plan for Climate Change research. The Forest Service is integrating climate change into National Forest Service Management Plans and is providing guidance to Forest Managers on how to respond and adapt to climate change. The Natural Resources Conservation Service and Farm Services Agency are encouraging actions to reduce GHG emissions and increase carbon sequestration through conservation programs. USDA's Risk Management Agency has prepared tools to manage drought risks, and is conducting an assessment of the risks of climate change on the crop insurance program. USDA is also providing guidance to landowners to enable them to estimate their greenhouse gas footprints.(Last Modified: 05/27/2008)"

U.S. Climate Change Science Program Alternate Download Site

Some key Excerpts on the likely regional effects of Global Warming from the Executive Summary:


Climate changes, temperature increases, increasing CO2 levels, and altered patterns of precipitation are already affecting U.S. water resources, agriculture, land resources, and biodiversity (very likely).
The literature reviewed for this assessment documents many examples of changes in these resources that are the direct result of variability and changes in the climate system, even after accounting for other factors. The number and frequency of forest fires and insect outbreaks are increasing in the interior West, the Southwest, and Alaska. Precipitation, streamflow, and stream temperatures are increasing in most of the continental United States. The western United States is experiencing reduced snowpack and earlier peaks in spring runoff. The growth of many crops and weeds is being stimulated. Migration of plant and animal species is changing the composition and structure of arid, polar, aquatic, coastal, and other ecosystems.

Climate change will continue to have significant effects on these resources over the next few decades and beyond (very likely).
Warming is very likely to continue in the United States during the next 25 to 50 years, regardless of reductions in greenhouse gas emissions, due to emissions that have already occurred. U.S. ecosystems and natural resources are already being affected by climate system changes and variability. It is very likely that the magnitude and frequency of ecosystem changes will continue to increase during this period, and it is possible that they will accelerate. As temperature rises,crops will increasingly experience temperatures above the optimum for their reproductive development, and animal production of meat or dairy products will be impacted by temperature extremes. Management of Western reservoir systems is very likely to become more challenging as runoff patterns continue to change. Arid areas are very likely to experience increases erosion and fire risk. In arid ecosystems that have not coevolved with a fire cycle, the probability of loss of iconic, charismatic megaflora such as Saguaro cacti and Joshua trees will greatly increase.

Many other stresses and disturbances are also affecting these resources (very likely).
For many of the changes documented in this assessment, there are multiple environmental drivers - land use change, nitrogen cycle changes, point and nonpoint source pollution, wildfires, invasive species - that are also changing. Atmospheric deposition of biologically available nitrogen compounds continues to be an important issue, along with persistent ozone pollution in many parts of the country. It is very likely that these additional atmospheric effects cause biological and ecological changes that interact with changes in the physical climate system. In addition, land cover and land use patterns are changing, e.g., the increasing fragmentation of U.S. forests as exurban development spreads to previously undeveloped areas, further raising fire risk and compounding the effects of summer drought, pests, and warmer winters. There are several dramatic examples of extensive spread of invasive species throughout rangeland and
semiarid ecosystems in western states, and indeed throughout the United States. It is likely that the spread of these invasive species, which often change ecosystem processes, will exacerbate the risks from climate change alone. For example, in some cases invasive species increase fire risk and decrease forage quality.
Member Since: September 16, 2005 Posts: 0 Comments: 3434
1651. LakeShadow
1:58 PM GMT on June 23, 2008
New Blog up
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1650. nrtiwlnvragn
9:58 AM EDT on June 23, 2008
New Blog
Member Since: September 23, 2005 Posts: 19 Comments: 12177
1648. Floodman
8:52 AM CDT on June 23, 2008
Good morning jp, mel, StormW, sport, Taz and Baha and everyone else, lurkers and other wise! Taz, where would one get a cool avatar such as yours?
Member Since: August 2, 2006 Posts: 10 Comments: 9948
1647. NEwxguy
1:51 PM GMT on June 23, 2008
Flood,can't imagine anyone putting you on ignore,the most sane person here.
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1644. sporteguy03
1:48 PM GMT on June 23, 2008
It is going to be a bright sunshiny day in Orlando hopefully no storms. Remember no spinning.
Member Since: July 7, 2005 Posts: 0 Comments: 5658
1642. melwerle
1:41 PM GMT on June 23, 2008
MOrning JP & Baha!
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1641. Tazmanian
6:39 AM PDT on June 23, 2008
has the big H set up shop yet?
Member Since: May 21, 2006 Posts: 5100 Comments: 117347
1640. BahaHurican
9:22 AM EDT on June 23, 2008
1631. Patrap 9:14 AM EDT on June 23, 2008

The Philipino president is remarkably unimpressive as a leader right now. She is "blasting everybody out", but she is also not putting herself in the place needed to ensure that things are done properly. If this is her normal management style, it's not surprising things are not being well handled.
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1638. melwerle
1:38 PM GMT on June 23, 2008
I'm around Flood - good morning! Just watching what's going on this morning...
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1637. Floodman
8:29 AM CDT on June 23, 2008
Am I the only one here, or am I on far more "Ignore" lists than I thouhgt?
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1636. TheWeatherMan504
1:28 PM GMT on June 23, 2008
its a quiet party alright.
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1635. Floodman
8:27 AM CDT on June 23, 2008
1626. stoormfury

You know, Stoorm, you shouldn't be picking up those trucks all by yourself...

All kidding aside, hope you're doing better
Member Since: August 2, 2006 Posts: 10 Comments: 9948
1634. Floodman
8:26 AM CDT on June 23, 2008
Welcome to the party, CATV!
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1633. Floodman
8:20 AM CDT on June 23, 2008
1614. ShenValleyFlyFish

Shen, you old softy! I thought you had a little tilt to the left...I agree; Xenophobia and racism are not the sole purview of Americans...humans are equal opportunity haters...
Member Since: August 2, 2006 Posts: 10 Comments: 9948
1632. Floodman
8:10 AM CDT on June 23, 2008

Thrilla, do you have data to back up this statement?
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1631. Patrap
8:10 AM CDT on June 23, 2008
ReliefWEB Link

Philippines: Typhoon Fengshen (as of 23 Jun 2008) - Situation Map
Philippines Situation Map

* Date: 23 Jun 2008
* Type: Natural Disaster
PDF Link

Source: Deutsche Presse Agentur (DPA)

Date: 23 Jun 2008

Relief efforts intensify as Typhoon Fengshen leaves Philippines

Manila_(dpa) _ Rescue and relief efforts intensified on Monday in the the aftermath of Typhoon Fengshen, which caused massive destruction in a large part of the Philippines and left at least 186 people dead and hundreds missing.

The weather bureau said Fengshen, with maximum sustained winds of 110 kilometres per hour and gusts of up to 140 kilometres per hour, was spotted Monday at sea 300 kilometres north-west of the northen city of Dagupan.

Fengshen, which was heading towards the general direction of Taiwan, will stay within the Philippine area of responsibility until Tuesday, the agency added.

Rescuers and relief workers continued to battle high floodwaters in several towns of Iloilo province, 465 kilometres south of Manila, where at least 101 people have been killed.

Iloilo Governor Neil Tupas said the death toll was expected to rise as dozens more remained missing.

Tupas said Fengshen was the worst typhoon to hit the city in more than three decades. He appealed for rubberboats to allow rescuers to penetrate hard-to-reach areas.

The southern region of Mindanao, which was first hit by the typhoon, suffered 21 fatalities. Nine were killed in Antique province, four in the central province of Capiz, two each in the provinces of Romblon, Batangas, Bulacan, Zambales, Quezon, Negros Occidental and Leyte.

The provinces Marinduque and Mindoro Oriental each reported one fatality.

The death toll includes 35 confirmed killed in the sinking of a passenger ferry carrying 849 people aboard off Sibuyan Island, 300 kilometres south of Manila, on Saturday. Thirty-eight survivors have been found, but more than 770 are still unaccounted for.

The United States was to dispatch a rescue vessel to help in the search for survivors from the sunken ferry.

The National Disaster Coordinating Council (NDCC) said Fengshen's damage to infrastructure and agriculture were initially estimated to cost 1 billion pesos (22.52 million dollars).

It noted that several areas throughout the country have remained unreachable due to high floodwaters and landslides, while electricity and communication were also still down in some areas.

President Gloria Macapagal Arroyo, who left Manila on Saturday for a 10-day visit in the United States, has scolded senior officials during a video teleconference about the high death toll.

Early Monday, Arroyo blasted the head of the NDCC for failing to come up with a consolidated report on the damage caused by Fengshen. On Sunday, she reprimanded the Coast Guard's head for allowing the Princess of the Stars to sail despite a tyhoon warning. dpa jg gl pw

Copyright (c) dpa Deutsche Presse-Agentur GmbH
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1630. NEwxguy
1:10 PM GMT on June 23, 2008
Tropics have arrived in New England,high humidity,thunderstorms popping up all over the place.
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1629. BahaHurican
9:01 AM EDT on June 23, 2008
CatV, welcome aboard! Looking forward to an interesting season.
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1628. 69Viking
7:43 AM CDT on June 23, 2008
1624. weathermanwannabe

Good Morning all! Yes the panhandle received some much needed rain this weekend. Still need more in my area. The dry ground soaked up every bit of rain like a sponge, no ponding anywhere to suggest the ground was saturated. Pretty quiet in the tropics.
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1627. CatV
12:40 PM GMT on June 23, 2008
Newby here: CATV. Good morning! I am in the U.S. Navy, 4 years, shipping out in about 30 days for advanced meteorology training.
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1626. stoormfury
12:23 PM GMT on June 23, 2008
i am back after two hernia repair operations, last tuesday. well the tropics looking extemely quiet and it appears it will be so for sometime i will take the time off for more recuperation until the season ramps up between the 1st and 2nd week of july. i will keep checking just in case something were to pop up
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1625. Weather456
8:17 AM AST on June 23, 2008
1607. msphar 2:31 AM AST on June 23, 2008
456 - until it drops off the land it tough to tell if it will transition to a wave over water.

I dont track tropical waves for development or I wudnt be looking at a wave over Sudan.
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1624. weathermanwannabe
7:58 AM EDT on June 23, 2008
Good Morning....Nice and rainy for the last 24 hours in North Florida and very quiet along the Gulf/SE coast in spite of the huge influx of moisture (training effect from the huge low over the Great Lakes)....Looking like June will remain quiet (and starting to wonder if we will "skip" the June/July climatology closer to home and start looking at CV storms a little earlier than usual (mid-July)...mmmmmmm..Just pondering.......
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1623. BahaHurican
8:00 AM EDT on June 23, 2008
Recent Fengshen imagery.

Doesn't look like much, prolly due to shear from that front that's approaching over China. I suppose that's what's going to take it off to the east again . . .
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1622. TheWeatherMan504
11:57 AM GMT on June 23, 2008
George Carlin Died last night im going to miss his shows.

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1621. BahaHurican
7:54 AM EDT on June 23, 2008
BTW, anybody looked at Fengshen's forecast track / strength overnight? I notice on the Navy site it's being forecast to move even further west than originally expected. Seems to be a trend with that storm. They don't expect it to strengthen back to hurricane status, but that could change.
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1620. BahaHurican
7:54 AM EDT on June 23, 2008
Morning StormW.
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1619. BahaHurican
7:49 AM EDT on June 23, 2008
From this morning's 8:05 TWD:



This is actually a pretty interesting set-up for this time of year.
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1617. BahaHurican
7:04 AM EDT on June 23, 2008
Notice the ITCZ in the CAR for the first time this season. This is the big shift week, if I remember correctly - by next Monday the ITCZ should be mostly at / above 10N . . . .
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1616. StormHype
11:42 AM GMT on June 23, 2008
TampaSpin said...
Gang we have a LLC developing in the BOC at 21N 94.5W.....Get ready it is moving NNE.

Poof. Next!

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1615. leftovers
11:16 AM GMT on June 23, 2008
Is that the leftovers of the tropical wave we followed just south of Jamaica? Look for a blowup in the western Carib. Hope everyone has a buena dia.
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1614. ShenValleyFlyFish
6:26 AM EDT on June 23, 2008
1598. HurakanPR

SOME U.S. Americans are xenophobic. Probably about the same % as any other country. Face it we are not that special.

Our lack of multiple language skills has more to do with the fact that the country occupies the better part of a continent. Most of us get to practice using another language only on rare occasions. If you are fluent in any languages other than Spanish and English I will be surprised. I actively attempted to learn Spanish. When I lived in the PR section of NYC I had daily occasion to at least listen to Spanish. I have rare need to use any Spanish in my current daily life. When it is it is with folks from Mexico and Texas. They tend to denigrate my abilities as Puerto Rican Spanglish. LOL

Prejudice is not the sole purview of any one group of people.

(how's that for a liberal rant?)

"I'm not prejudiced. I hate everyone equally." W.C. Fields
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1612. weathermanwatson
10:49 AM GMT on June 23, 2008
Discussion from the Tallahassee NWS...

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1611. jaikishan
10:44 AM GMT on June 23, 2008
I live in Trinidad and there is a small Philipino population here, just about a few hundred. I join them in extending my deepest sympathies to all affected by the typhoon last week.Let us all remember to respect life regardless of what nationality...
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1610. TheWeatherMan504
10:44 AM GMT on June 23, 2008
1567. SpaceThrilla1207 3:22 AM GMT on June 23, 2008 Hide this comment.
I agree with JP, nothing will form out of our BOC low and this will be a more tranquil year than expected...In my opinion this will be a 2006 type year.

wow its june if it was quiet like this in august then i would be concerned but its not august. even 2005 had 2 and 2004 had none! you should not even go on this site if you are going to say such an ill-logical comment.You need to think before you comment.
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1609. NorthxCakalaky
7:52 AM GMT on June 23, 2008
N.C Flood report

06/22/2008 1034 PM

Charlotte, Mecklenburg County.

Flash flood, reported by Emergency Mngr.

Car floating in wal-Mart parking lot on wilkson Blvd

06/22/2008 1030 PM

Charlotte, Mecklenburg County.

Flash flood, reported by Emergency Mngr.

North Tryon and 16th street flooded

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1608. moonlightcowboy
2:07 AM CDT on June 23, 2008
I saw that, 456, and posted a shot at 1593. That could be the one that sneeks in on us. The other conditions seem to be coming together.
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1607. msphar
6:26 AM GMT on June 23, 2008
456 - until it drops off the land it tough to tell if it will transition to a wave over water.
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1606. Weather456
1:30 AM AST on June 23, 2008
Continuing to track a classic African Easterly Wave

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1605. johnrsharp
12:42 AM CDT on June 23, 2008
What about the flood of 1927? Do we have three 500 year floods in 80 years? I remember in Oregon, there was a 500 year flood. 30 years later there was a worse one. After checking archives of the settlers, it turned out there was a flood about as bad in 1899.

Maybe these extreme events are more common than people realize.
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1604. weatherblog
5:16 AM GMT on June 23, 2008
Space, were do you get your Data from? How So? You realize its only June and we already have had Arthur? Do you have any Charts and Graphs to indicate a Slow Season? Do you know that it only takes one? If your going to consider tranquill seasons, that would place 1992 under that.. With Hurricane Andrew. On this blog its best not to say opinions on the whole season without Data and info. If you do, I'd gladly love to see it.

Agree completely.
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Dr. Masters (r) co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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