Weekend tornado outbreak causes heavy damage in Virginia, Iowa

By: Dr. Jeff Masters , 2:00 PM GMT on April 11, 2011

Share this Blog
3
+

Floods, fires, and tornadoes hammered the nation this weekend, a sure sign that April is here. The severe weather action began on Friday night in the mid-Atlantic when twin tornadoes touched down in Pulaski, Virginia. The twisters, one a strong EF-1 with 105 - 110 mph winds, and the other an EF-2 with 125 mph winds damaged 450 buildings, caused $8 million in damage, and injured eight people. The most significant day of the weekend tornado outbreak occurred on Saturday as a powerful storm over the Upper Midwest dragged a cold front through Iowa. Twenty-seven tornado reports were recorded in Iowa by NOAA's Storm Prediction Center. The most powerful of these tornadoes was the huge, 3/4 mile-wide tornado that plowed through the tiny town of Mapleton, Iowa on Saturday evening, leaving a trail of destruction 3.5 miles long. The tornado, preliminarily rated as an EF-3 with 136 - 165 mph winds, flattened 20% of the town of 1200 residents and damaged half of the buildings. Fourteen were injured, but miraculously no one died. The severe weather continued on Sunday with seven reports of tornadoes over Wisconsin. The most serious was a tornado in Lincoln County, which destroyed or heavily damaged 30 buildings, and caused three serious injuries.


Figure 1. Tornado chaser video from Saturday's twisters over Iowa from tornadovideos.net.

More severe weather today
As the cold front that triggered the weekend's severe weather progresses eastwards across the U.S. today, NOAA's Storm Prediction Center has placed a wide swath of the Northeast and Southeast under their "slight" risk area for severe weather, one notch down from the "Medium" risk that was posted for Wisconsin on Sunday and Iowa on Saturday. Tuesday and Wednesday should be relatively quiet days for severe weather, but Thursday will see a renewed chance of a significant severe weather outbreak in the Oklahoma-Arkansas region, as a major new spring storm gathers strength over the Midwest.


Figure 2. Severe weather outlook from NOAA's Storm Prediction Center for Monday places much of the Northeast and Southeast in the "Slight" risk area for severe weather.

Tornado season near average so far this year
According to statistics compiled by NOAA's Storm Prediction Center, 2011's tornado season has been near-average so far. The preliminary number of tornadoes reported as of April 10 was 301, and the six-year average from 2006 - 2010 was 339. Preliminary tornado counts are typically about 15% too high, so the actual number of confirmed tornadoes will end up being around 256. The peak part of tornado season is just getting started--typically, only 17% of the season's activity has occurred by April 10. The number of strong (EF-2 and EF-3) tornadoes has been rather low so far; the Mapleton tornado was just the seventh EF-3 of 2011. There have been no violent EF-4 or EF-5 tornadoes so far this year. The death toll of just three so far in 2011 is remarkably low for mid-April, a testament to good warnings and a good helping of luck.

Jeff Masters

Cold in April (Railheel)
Hail, wind, and rain came through with unknow damage as of now. did break windshilds.
Cold in April
Tornado-damaged house (ChrisAnthemum)
Early Tuesday morning, a tornado raked along Ararat Road in Pilot Mountain, NC, damaging several houses and downing many trees. A cleanup crew was working on this one when we drove by on Sunday.
Tornado-damaged house

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 117 - 67

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9Blog Index

Quoting beell:


Mainly due to surface heating that drives the lapse rates. Warm and hot in the low levels, cooler air aloft. Leads to explosive development. Dry line works the same way except you get the added kick from a surface boundary to increase low-level shear.
I f you can, please explain to me why there are 2 squall lines forming in such close vicinity to one another..Doesnt one rob energy from the other?
Member Since: Posts: Comments:
Quoting Jax82:
Awesomm pic thnx Jas82.
Member Since: Posts: Comments:
The CPC update today showed that the Nino 3.4 region had risen to -0.6C below normal, just below the threshold for La Nina. It still has to rise a full degree celsius to achieve El Nino conditions, but it's only April. An El Nino could be in the making.
Member Since: Posts: Comments:
114. beell
Quoting jeffs713:

Those dry lines tend to be rather lackluster in convection, based on what I've seen. The ones that seem to have the most pop is when dry air is intruding in on moist air. Not sure about other parts of the country, but the cells that get their start on dry air intrusions like that tend to be some of the nastiest in N TX.


Mainly due to surface heating that drives the lapse rates. Warm and hot (duh-repetitive)in the low levels, cooler air aloft. Leads to explosive development. Dry line works the same way except you get the added kick from a surface boundary to increase low-level shear.
Member Since: September 11, 2007 Posts: 142 Comments: 16487
113. Jax82
Member Since: Posts: Comments:
Quoting TampaSpin:



Dang another Quake in Japan....going on a bike ride. Everyone be safe.
I feel for the people in Japan... they have to be a rattled wreck (in more ways than one).

I don't recall any recent great quake with this many aftershocks of this magnitude. A few 7s and 6s, ok, but this quake is ripping off 5s and 6s for aftershocks like they are nothing.
Member Since: Posts: Comments:
The western edge of tornado watch box 129 ends about 10 miles from home, and the bad weather is advancing eastward. Tornado watches are unusual in my area, and tornadoes even more so. I have only seen two in my life, and one of those wasn't near my hometown- and I'm not as young as I used to be :) Please be careful, all!
Member Since: Posts: Comments:



Dang another Quake in Japan....going on a bike ride. Everyone be safe.
Member Since: Posts: Comments:
Quoting beell:
101. TampaSpin 6:16 PM GMT on April 11, 2011

a Dry Line is developing in front of the LOw into Mississippi


Way over here in Texas, we call that a cold front. No dryline today. We'll have to wait for high pressure behind the front to slide east with the western edge of moisture return delineating the dry line a from the warm, moist retun flow up the west side of surface high pressure.

Those dry lines tend to be rather lackluster in convection, based on what I've seen. The ones that seem to have the most pop is when dry air is intruding in on moist air. Not sure about other parts of the country, but the cells that get their start on dry air intrusions like that tend to be some of the nastiest in N TX.
Member Since: Posts: Comments:
Quoting beell:
101. TampaSpin 6:16 PM GMT on April 11, 2011

a Dry Line is developing in front of the LOw into Mississippi


Way over here in Texas, we call that a cold front. No dryline today. We'll have to wait for high pressure behind the front to slide east with the western edge of moisture return delineating the dry line a from the warm, moist retun flow up the west side of surface high pressure.



You can see the start if the line i am referring now starting up in Northern Louisiana.

Member Since: Posts: Comments:
104. beell
101. TampaSpin 6:16 PM GMT on April 11, 2011

a Dry Line is developing in front of the LOw into Mississippi


Way over here in Texas, we call that a cold front. No dryline today. We'll have to wait for high pressure behind the front to slide east with the western edge of moisture return delineating the dry line a from the warm, moist retun flow up the west side of surface high pressure.
Member Since: September 11, 2007 Posts: 142 Comments: 16487
Member Since: Posts: Comments:






After looking at everything, my best guess would be the Northern Half of Mississippi and Northern Alabama is my main Target for Tornado's. If you look at everything above on the WV loop you can see a Double punch LOw's. The one moving out of the MidWest is most disturbing because a Dry Line is developing in front of the LOw into Mississippi. That will fill in later and begin to explode latter in my opinion. Little more warmer and humid temps in that area than in the North....Don't get me wrong any of the Box area is a threat as the Second Low Near Ohio is gonna be a problem into West Virginia and Pennsylvania as well.
Member Since: Posts: Comments:
Good afternoon! It's a lovely mid 70's here in Chattanooga TN.
Member Since: Posts: Comments:
Quoting DestinJeff:


Thanks. That is very nice of you. I don't post much at all during non-hurricane season, and we are getting clode enough now that I will be on more and more.

I enjoy everyone's input ... not just the serious stuff.
Yes...Good to see you posting jeff...,Now...Please praise the emblem of the generative power...
Member Since: Posts: Comments:
Quoting TampaSpin:



I posted it on WU while it was occurring..........for sure an evil looking thing it appeared.


Sorry I missed your posting last night, I was a bit preoccupied :)

Looking at the video and images posted from Mapleton, IA as well as the other severe weather across the region the past few days, I'm really impressed there were no fatalities. I will take a moment to give kudos to the SPC and the local NWS offices for the lead times on watches and warnings. Our technology has come a long way and is likely preventing natural disasters from being worse.

Just as an example, I looked up the deadliest tornado recorded in Wisconsin. 117 people died and another 125 were injured on 12 June 1899 the western portion of the state. We can only speculate what the death toll would be, but a little warning time can go a long way.
Member Since: Posts: Comments:
Quoting hydrus:
The forecast keeps getting worse here...Looks like the shutters go up here too....


I'd say that might be a good idea.



MESOSCALE DISCUSSION 0413
NWS STORM PREDICTION CENTER NORMAN OK
1237 PM CDT MON APR 11 2011

AREAS AFFECTED...SWRN TN AND FAR NRN MS

CONCERNING...TORNADO WATCH 128...

VALID 111737Z - 111830Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 128 CONTINUES.

INCREASED POTENTIAL FOR A TORNADO EXISTS ACROSS SWRN TN AND FAR NRN
MS DURING THE EARLY AFTERNOON...INCLUDING THE MEMPHIS METRO AREA BY
18Z.

RECENT SURFACE ANALYSIS SHOWED A WIND SHIFT ATTENDANT TO A
CONVECTIVE OUTFLOW BOUNDARY EXTENDING FROM SRN KY SWWD THROUGH
MIDDLE TN AND WSWWD INTO FAR SWRN TN...ALONG AND S OF MEM. ELY
SURFACE WINDS OVER WRN TN ARE ENHANCING LOW LEVEL SHEAR WITH THE MEM
WSR-88D VWP INDICATING SURFACE-1 KM VALUE CLOSE TO 40 KT AND 0-1 KM
SRH AROUND 375 M2/S2. AT 1730Z...REGIONAL RADAR IMAGERY SHOWED A
WELL ORGANIZED STORM OVER FAR EAST CENTRAL AR APPROACHING MEM AT 45
KT FROM THE WSW. AS THIS STORM REACHES THE MEM AREA...THE
AFOREMENTIONED ENHANCED LOW LEVEL SHEAR SUGGESTS A GREATER POTENTIAL
FOR LOW LEVEL STORM ROTATION AND A TORNADO THREAT.

OTHERWISE...EFFECTIVE SRH 200-300 M2/S2 EXTENDS ACROSS WW 128.
LIGHTNING DATA SHOWED TSTMS EXTENDING FROM FAR WRN TN SSWWD THROUGH
ERN TN TO FAR NRN LA. THIS ACTIVITY WILL PERSIST EWD INTO WW 128
POSING A THREAT FOR DAMAGING WINDS AND A TORNADO THREAT.

..PETERS.. 04/11/2011
Member Since: Posts: Comments:
Quoting Jedkins01:



I know there was some damage and some severe weather reports, but certainly not to warrant the PDS they had out yesterday. Here in Central Florida we've had a few severe weather events worse than that this year. But its good that it wasn't too bad! That high of a risk that far north and this early in the season sounded a bit fishy to me. The far northern plains get a lot more action in May and June typically. April usually isn't as big for them. Come the summer months the strongest upper level energy is usually in the northern plains and that combined with high temperatures, higher moisture and shearing leads to bigger events up there.


Except in a year following a La Nina winter.
A shift in tornado activity is common.

Palm Sunday Outbreak in '65
Super Outbreak in '74
Both in early April
Both following La Nina
Both in the midwest/OH/TN Valleys
Member Since: September 11, 2007 Posts: 142 Comments: 16487
Quoting 47n91w:


The preliminary damage assessment has rated the Adams County tornado as EF2. They're measuring the damage path right now but it seems there was a tornadic circulation on radar for 25 minutes.

Having said that, yes, perhaps you're right... in hindsight a PDS watch might have been a little over-the-top but I'll take some extra caution versus not enough. And we do seem to have a bit of a complacency problem in WI when it comes to severe weather.



I posted it on WU while it was occurring..........for sure an evil looking thing it appeared.
Member Since: Posts: Comments:
Quoting Jedkins01:



I know there was some damage and some severe weather reports, but certainly not to warrant the PDS they had out yesterday. But its good that it wasn't too bad! That high of a risk that far north and this early in the season sounded a bit fishy to me. The far northern plains get a lot more action in May and June typically.


The preliminary damage assessment has rated the Adams County tornado as EF2. They're measuring the damage path right now but it seems there was a tornadic circulation on radar for 25 minutes.

Having said that, yes, perhaps you're right... in hindsight a PDS watch might have been a little over-the-top but I'll take some extra caution versus not enough. And we do seem to have a bit of a complacency problem in WI when it comes to severe weather.
Member Since: Posts: Comments:
The latest situation report from Wisconsin Emergency Management:

DATE: April 11, 2011, 11:00 a.m.
TO: Governor Scott Walker
FROM: Mike Hinman, WEM Administrator
SUBJECT: Situation Report #1 on Severe Weather


Last night’s storms brought heavy rains, hail and suspected tornadoes to much of Wisconsin, with the Northeast and East Central regions reporting the heaviest damages to homes and businesses. Many county emergency management directors are assessing their local damages today. All tornado reports are tentative until confirmed by the National Weather Service.

Adams County:
Representatives from the county emergency management, police and sheriff’s departments are assessing damage from an unconfirmed tornado in the area of Big Flats/Cottonville:

From east to west: 11th Avenue, west to Cottonville dam


From north to south: Chicago Avenue to Cree Avenue


Calumet County:
Minor damage reported to around a dozen homes.

Forest County:
Reports of minor damage from a suspected tornado touchdown.

Kewaunee County:
County Trunk X is shut down for at least two or three days due to erosion caused by water crossing the road.

Culvert pipes are plugged in numerous areas causing erosion to multiple roads and embankments throughout the county. Water has pooled up to six feet in diameter on some roads.

Lincoln County:
A suspected tornado hit shortly after 6:00 pm last night. The County EOC is partially activated. An incident command post is set at the intersection of Taylor and Pierce Streets in Merrill. A perimeter has been set with the State Patrol at check points, and no one is being allowed entry at this time.

Local States of Emergency have been declared. State agencies on scene include WEM, DNR and State Patrol and the Red Cross.

Three serious injuries required helicopter transport, but no deaths were reported.

The damage path is from SW to NE with concentrations in a 2-3 mile (approximate) path along the north city limits. Gas and power have been shut off to the area. Six gas crews and 20-plus power crews are on the scene.

An initial assessment shows that seven businesses in the industrial park were destroyed and 20 to 25 homes were either destroyed or have sustained major damage. 25 to 50 other homes have sustained other damages. No insurance information is available at this time on the properties.

Congregate care is being run by Red Cross at AmericInn. No one stayed overnight, as displaced residents sought shelter with family and friends.

Merrill area public schools are closed for the day.

Damage assessments began in the county at 8:30 am, and an additional briefing is expected from the county at noon.

No additional resources have been requested for Lincoln at this point.

Marathon County:
Damages were reported from the Town of Holton along County FF to US 51. Reports of one house damaged/destroyed, shed and barns damaged in the Hamburg area on either side of FF. Reports of trees and power lines down in this area.

Outagamie County:
Outagamie is continuing their damage assessment, and is expecting to declare a disaster for City of Kaukauna and Outagamie County. Reports of pea-sized hail, heavy rain, trees down, power lines down. City of Kaukauna is reporting damaged homes.

Winnebago County:
Reports of trees down and roof and window damages to some homes. One business with major damage in Town of Menasha, with the roof and one wall collapsed. Downed power lines reported, but most power is on. County emergency management still taking reports of damages.

There are no additional requests for any assistance from the affected areas at this time.

###
Member Since: Posts: Comments:
88. IKE

Quoting twincomanche:
I am in Northern Illinois right now and the price this morning was $4.079
:(
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting 47n91w:


There were about 6 reports of tornadoes across the state yesterday. Damage surveys are taking place now. Here's a quick map of some of the storm reports from NWSO Minneapolis:

Orange dots are damaging winds
Blue dots are large hail
Green dots are flash flooding





I know there was some damage and some severe weather reports, but certainly not to warrant the PDS they had out yesterday. Here in Central Florida we've had a few severe weather events worse than that this year. But its good that it wasn't too bad! That high of a risk that far north and this early in the season sounded a bit fishy to me. The far northern plains get a lot more action in May and June typically. April usually isn't as big for them. Come the summer months the strongest upper level energy is usually in the northern plains and that combined with high temperatures, higher moisture and shearing leads to bigger events up there.
Member Since: August 21, 2008 Posts: 0 Comments: 7401
Quoting beell:


Still pretty much over my head also EYES. But it sounds good! Sorry I left you off the response. Was trying to type/read/and feign interest in a conference call while dreaming of lunch.


Your just a "Multi-Tasker Plus" :)
Member Since: Posts: Comments:

Visit msnbc.com for breaking news, world news, and news about the economy

Member Since: Posts: Comments:
Greetings,

Stay watchful, I don't think I have ever heard the torndado horns go off in my town.

It look like the loop current is getting ready to spin off.

cheers.
Member Since: Posts: Comments:
Quoting EYEStoSEA:


OH, Lordy.....over MY head....I said...LOLOL


Still pretty much over my head also EYES. But it sounds good! Sorry I left you off the response. Was trying to type/read/and feign interest in a conference call while dreaming of lunch.
Member Since: September 11, 2007 Posts: 142 Comments: 16487

Visit msnbc.com for breaking news, world news, and news about the economy

Member Since: Posts: Comments:
Quoting DestinJeff:
So do we all agree to not compare 2011 maps to 2005 maps? That is in The Rules of the Road I think.

Gulf waters near Destin still shock to the system upon entry, but tolerable. The other 10 factors involved with getting a TC going are inconsequential.


I must take this opportunity to say...welcome back, and you were MISSED !!
Member Since: Posts: Comments:
Light Crude vs. Natural Gas


Member Since: Posts: Comments:
76. IKE

Quoting twincomanche:
Oil -$2.30 $110.49
Just went to town. Gas has gone from $3.73.9 to $3.85.9 per gallon...regular unleaded.

Out at the interstate area it's $3.98.9 per gallon.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting beell:


And I may be wrong. Cross checking with the SPC Meso Page this would be Mixed Layer (MLCAPE) and Mixed Layer Convective Inhibition (MLCINH) sine there is not much left to the capping inversion at this point.


And gro, since we are changing from surface based to mixed layer you are indeed 100% correct. It is over your head.
)

MLCAPE takes the bottom 100mb of atmosphere and mixes it all up and offers it to the storm updraft. If instability is shallow after this mixing is done, CAPE values will be lower.

SBCAPE computes instability from a surface parcel and may not paint a true picture.


OH, Lordy.....over MY head....I said...LOLOL
Member Since: Posts: Comments:
Quoting jitterboy:

Thanks!


And I may be wrong. Or the chart is old. Cross checking with the SPC Meso Page this would be Mixed Layer (MLCAPE) and Mixed Layer Convective Inhibition (MLCINH) sine there is not much left to the capping inversion at this point.


And gro & hydrus, since we are changing from surface based to mixed layer you are indeed 100% correct. It is over your head.
)

MLCAPE takes the bottom 100mb of atmosphere and mixes it all up and offers it to the storm updraft. If instability is shallow after this mixing is done, CAPE values will be lower.

SBCAPE computes instability from a surface parcel and may not paint a true picture.
Member Since: September 11, 2007 Posts: 142 Comments: 16487


2 separate lows!!!
Member Since: Posts: Comments:
Quoting Jedkins01:


hunker down boys, hunker down!
The forecast keeps getting worse here...Looks like the shutters go up here too....
Member Since: Posts: Comments:
Quoting Grothar:


Who would have guessed? (keep it up beel)


~~~~over my head~~~~:)
Member Since: Posts: Comments:
Quoting jeffs713:

Gee willikers, the front isn't obvious on that map AT ALL.

(and nasty shear incoming for the TN valley...
I hope it is not to bad here..But I have a gut feeling it will be rough this afternoon in Middle TN.
Member Since: Posts: Comments:
Quoting beell:


RUC-Surface base CAPE (SBCAPE) and Convective Inhibition (CINH).


Who would have guessed? (keep it up beel)
Member Since: Posts: Comments:
Quoting beell:


RUC-Surface base CAPE (SBCAPE) and Convective Inhibition (CINH).

Thanks!
Member Since: Posts: Comments:

Viewing: 117 - 67

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.