Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather
By: Dr. Jeff Masters , 5:24 PM GMT on May 01, 2014
The deadly and devastating U.S. severe weather outbreak of April 27 - 30, 2014, has finally drawn to a close. The death toll from nature’s 4-day rampage of deadly tornadoes, extreme flooding, and damaging severe thunderstorms has killed at least 39 people, and will end up costing more than $1 billion, according to disaster expert Steve Bowen of Aon Benfield. NOAA’s Storm Prediction Center (SPC) lists 133 preliminary tornadoes over the four days in 14 states; damage surveys are on-going, and 38 of these tornadoes had been confirmed as of noon on May 1.
Figure 1. Rainfall derived from the TRMM' satellite’s Microwave Imager (TMI) and Precipitation Radar (PR) data is shown overlaid on GOES-EAST infrared satellite images captured on April 29, 2014 at 0402 UTC and 0532 UTC. Red symbols show the locations where numerous tornadoes were reported from Monday afternoon through Tuesday morning. Image credit: NASA.
Extreme rainfall and flooding in Pensacola and Mobile
Torrential rains on Tuesday night in Pensacola, Florida brought an all-time calendar-day record of 15.55” of rain to the city. The old calendar day record of 15.29" in October 1934 was due to a tropical storm that made landfall just to the west of the city. Mobile, Alabama saw 11.24" during the calendar day on Tuesday, their 3rd greatest calendar day total on record. The Pensacola Airport recorded a remarkable 5.68 inches of rain in just one hour ending at 10 pm Tuesday night, and numerous high-water rescues had to be performed Tuesday night and Wednesday morning. One drowning occurred, in a vehicle that tried to cross flooded Highway 29. According to a nice flood event summary from the Mobile/Pensacola NWS, the 5.68" that fell in 1 hour was between a 1 to 200 and 1 to 500 year event, and the two day estimated total for Pensacola of 20.47" lies between a 1 in 100 to 1 in 200 year event. As discussed by Andrea Thompson at Climate Central, these type of extreme precipitation events have increased in the U.S. in recent decades, are are expected to continue to increase as a warming climate puts more moisture into the atmosphere. A comparison for perspective: Wichita, Kansas is having it's second driest start to the year since 1936, with 2.01” since January 1, 2014; Pensacola received 2 1/2 times as much rain in one hour than Wichita has seen all year. Pensacola finished April with 29.53” of rain, breaking the all-time record for any month (not just April) of 24.46” set in April 2005. This also makes it the wettest year-to-date on record in Pensacola.
Figure 2. Natural gas leaks spray into the sky on Piedmont Street in the Cordova Park neighborhood in Pensacola, Florida, after the road washed out due to heavy rains on April 30, 2014. (Photo by Marianna Massey/Getty Images)
Video 1. Aerial drone footage of the Scenic Highway near Pensacola, Florida, after being washed out by extreme flooding on April 30, 2014. Another YouTube drone video here of the Pensacola flooding also shows the impressive scale of the event.
Heavy rains and flooding in the Mid-Atlantic and Northeast
The storm also brought heavy rains and damaging flooding to much of the Mid-Atlantic and Northeast on Wednesday. The 4.97" that fell in New York City at Central Park was the Big Apple’s 2nd wettest April day on record, behind the 7.57" that fell on April 15, 2007. In Pennsylvania, during a nine-hour period that ended early Thursday, Chester County got 6.6 “ of rain, Delaware and Montgomery counties got 5.5”, and Philadelphia nearly 5 inches. At least 62 people were rescued overnight in Chester County from their vehicles, most after driving past closed road signs and barriers. Heavy rains in Baltimore caused a washout of a retaining wall, causing multiple cars to plunge down into a flooded railway line.
Figure 3. View of the Charles Village, Baltimore retaining wall collapse near 26th St on April 30, 2014. There were no injuries, but at least six cars plunged down onto the CSX railroad tracks below. According to meteorologist Justin Berk, who took the photo, local residents said they have had concerns about this wall for a long time.
Two EF-4 tornadoes from the outbreak
At least two EF-4 tornadoes have been surveyed so far from the outbreak, and there may be others once damage surveys are complete:
Vilonia, Arkansas: A violent high-end EF-4 tornado with winds of 180 - 190 mph tore through Vilonia and Mayflower, Arkansas on April 27, killing 15 people. This tornado was also the widest (3/4 mile) and longest lived (60 minutes) twister of the outbreak. There is a report that the tornado picked up a truck in Mayflower and deposited it in a field northeast of Vilonia, 27 miles away. Update: When contacted about this again by a reporter, the man who's car was transported admitted some confusion about where his car had been parked at the time of the tornado, so this remarkable story is dubious.
Louisville, Mississippi: An EF-4 with 185 mph winds hit Louisville, Mississippi on April 28. The tornado killed nine people, carved a path 35 miles long and up to 3/4 mile wide, and stayed on the ground for 56 minutes. The tornado carried a door 30 miles from Louisville and deposited it on the Mississippi State University campus.
The longest path tornado of the event was an EF-1 twister with a path length of 46 miles that stayed on the ground 46 minutes, and killed two people near Martinsburg and Kinross, Iowa on April 27.
Figure 4. Volunteers help clean up debris where homes once stood after the area was hit by a tornado April 29, 2014 in Vilonia, Arkansas. (Photo by Mark Wilson/Getty Images)
Video 2. Aerial drone footage of tornado damage from April 28, 2014 in Bessemer, Alabama just west of Birmingham. The EF-2 tornado with maximum winds of 120 mph stayed on the ground 4.9 miles and hit a golf course and an apartment complex, with a near miss of the Bessemer Hospital. It’s remarkable to see the huge number of trees pulled out by their roots. According to an article in Forbes, “The FAA claims the broad authority to prohibit the ‘commercial’ use of drones, and has included the use of drones for journalism or search and rescue under that ban. The FAA’s determination comes despite having lost an enforcement action at the administrative judge level….Despite the clear value of drones in disaster response and search and rescue operations, one search and rescue group based out of Texas has been forbidden from flying their drones in search and rescue operations, prompting them to sue the federal government. That case has sent a message to all would be search and rescue groups, letting them know they should keep their drones grounded, lest they face fines for trying to help find lost persons.”
U.S. billion-dollar weather-related disasters of 2014
1) The January 5 - 8 "Polar Vortex" winter weather outbreak, which Aon Benfield estimated caused $3 billion in damage.
2) The California drought, with $3.6 billion in agricultural damages so far, as estimated by the California Farm Water Coalition.
3) Severe weather outbreak of April 27 - 30, which Aon Benfield estimated caused $1+ billion in damage.
Disaster Relief Donations Needed
The devastation from this week’s tornadoes have brought a need for donations for disaster relief. The Portlight.org disaster relief charity, founded by members of the wunderground community, is supporting the efforts of a group of local volunteers in Arkansas doing search and rescue, and needs donations. Portlight volunteers are working in tornado-hit towns to clear debris and help with other clean-up efforts. This team will also be visiting shelters and reaching out to survivors with disabilities to determine their immediate needs, whether for replacement of durable medical equipment and ramps, or for assistance with shelter and transportation issues. The Red Cross is also a great place to send your donation dollars.
This will likely be my last post until Tuesday afternoon, as I plan on taking a few days off.
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