Storm Survey Status This page will be updated with the latest status for ongoing and planned storm surveys for major tornado outbreak of April 27, 2011. Due to the immense scope of the event, both in the degree of damage and the large geographical area that it covered, it will likely be a week or more before all surveys can be finalized.
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Showing posts with label April 27 Aftermath. Show all posts
Showing posts with label April 27 Aftermath. Show all posts
Saturday, April 30, 2011
April 27 Aftermath: Updated Tornado Surveys (April 30) Birmingham, AL
April 27 Historic Tornado Death Toll Continues to Climb (April 30)
The death toll from the April 27 tornado outbreak has risen to 355 people dead.
The National Weather Service also reported 211 confirmed tornadoes on that horrible day.
There were the most deaths in Alabama, with 254 deaths reported.
Tennessee and Mississippi followed respectfully in 2nd and 3rd place, each with 34 deaths.
In 4th place came Georgia with 15 deaths.
Arkansas- 11
Virginia- 5
Kentucky and Louisiana each had 1 death.
The National Weather Service also reported 211 confirmed tornadoes on that horrible day.
There were the most deaths in Alabama, with 254 deaths reported.
Tennessee and Mississippi followed respectfully in 2nd and 3rd place, each with 34 deaths.
In 4th place came Georgia with 15 deaths.
Arkansas- 11
Virginia- 5
Kentucky and Louisiana each had 1 death.
Friday, April 29, 2011
April 27 Aftermath: 4/29 Preliminary Results of Tornadoes (Birmingham, AL NWS Office)
Location(s) | Damage Survey Status |
| Hackleburg | EF-3+ Tornado. Winds: At least 180mph. Path Length: 25.2 miles, Path Width 3/4 mile. Further Evaluation Underway. |
| Other portions of Marion, Lamar, Fayette, and Winston Counties | Shotsville: EF-3+ Tornado. Winds: Around 140mph. Path Length: 19.1 miles in Marion County . Path Width: 3/4 mile. Further Evaluation Underway. Haleyville: EF-3+ Tornado. Winds: Around 140mph.Path Length: 31.8 miles, Path Width: 3/4 mile. The track may have continued into the Tennessee Valley. |
| Pickens County into Northern Tuscaloosa County | Ongoing (Aerial) |
| Walker and Blount Counties | Ongoing (Aerial) |
| Tuscaloosa | Ongoing (will likely take several days) |
| Jefferson County/Birmingham Metro | Ongoing (will likely take several days) |
| Western portions of Tuscaloosa-Birmingham Supercell (Sumter and Green Counties) | Ongoing Today |
| Eastern portions of Tuscaloosa-Birmingham Supercell (Saint Clair to Cherokee County) | Ongoing Today |
| Sumter-Green-Hale-Bibb-Shelby Counties | Being Finalized |
| Pell City-Talladega-Calhoun-Cleburne Counties | Saturday 4/30 |
| Marengo (continuation from Choctaw County) | Being Finalized |
| Perry-Dallas-Chilton Counties | Saturday 4/30 |
| Autauga-Elmore-Tallapoosa-Chambers (including Dadeville) | Ongoing Today |
April 27 Aftermath: How did the Tornado Outbreak occur?
Such an outbreak like the April 27 one is extremely rare and historic when it happens.
The big question is, how did this happen?
1. JET STREAM
The jet stream was down south, guiding the low pressure center east with the cold front that would produce the tornadoes. The jet stream was unusually strong, and the storm system may have even gotten some of that energy from the jet stream.
The jet stream made for a high wind shear event, favorable for tornadoes in some areas.
Additionally, the jet stream separates warm and cold air. With the cold front bringing the cold air from above the jet stream and the warm front bringing warm air from below the jet stream, it was a very volatile situation to start with.
2. EHI
EHI (Energy Helicity Index) combines wind factors (like helicity, which is a spinning motion) and energy factors (like CAPEs, which produce stronger and more volatile storms) to make a sense of what the potential is for rotating supercells.
The EHI index was incredibly high for the outbreak.
Values may have reached 12.00, which is considered absolutely unbelievable.
This is probably the biggest factor that directly contributed to the tornado outbreak.
3. CAPE
CAPE values indicate potential energy that can be utilized by thunderstorms. The higher the CAPE, the more unstable the atmosphere. CAPE values were witnessed to be up to 4,000 j/kg, possibly even more.
To give you a sense of how unstable 4,000 j/kg is, 2,000 j/kg is considered the threshold for severe thunderstorms for CAPE values.
There were many other things that came into place, but these 3 really stood out from the other factors.
Stay tuned to the Weather Centre for continuing coverage on the aftermath of this horrific incident.
The big question is, how did this happen?
1. JET STREAM
The jet stream was down south, guiding the low pressure center east with the cold front that would produce the tornadoes. The jet stream was unusually strong, and the storm system may have even gotten some of that energy from the jet stream.
The jet stream made for a high wind shear event, favorable for tornadoes in some areas.
Additionally, the jet stream separates warm and cold air. With the cold front bringing the cold air from above the jet stream and the warm front bringing warm air from below the jet stream, it was a very volatile situation to start with.
2. EHI
EHI (Energy Helicity Index) combines wind factors (like helicity, which is a spinning motion) and energy factors (like CAPEs, which produce stronger and more volatile storms) to make a sense of what the potential is for rotating supercells.
The EHI index was incredibly high for the outbreak.
Values may have reached 12.00, which is considered absolutely unbelievable.
This is probably the biggest factor that directly contributed to the tornado outbreak.
3. CAPE
CAPE values indicate potential energy that can be utilized by thunderstorms. The higher the CAPE, the more unstable the atmosphere. CAPE values were witnessed to be up to 4,000 j/kg, possibly even more.
To give you a sense of how unstable 4,000 j/kg is, 2,000 j/kg is considered the threshold for severe thunderstorms for CAPE values.
There were many other things that came into place, but these 3 really stood out from the other factors.
Stay tuned to the Weather Centre for continuing coverage on the aftermath of this horrific incident.
Thursday, April 28, 2011
Death Toll from Historic April 27 Tornado Outbreak Spikes
The death toll from last night's tornado outbreak has unfortunately spiked.
At least 173 people are confirmed dead.
Mississippi: 32
Alabama: 128
Dekalb County in Alabama was the hardest hit, with 30 people dead there alone.
There are also fatalities in Arkansas, Georgia, Tennessee.
A witness to the tornado that hit Birmingham indicated it was at least a mile wide.
The mayor of Tuscaloosa described Tuscaloosa's infrastructure as 'decimated'.
80,000 chickens escaped as well.
The Weather Centre holds people affected in our thoughts and prayers today.
At least 173 people are confirmed dead.
Mississippi: 32
Alabama: 128
Dekalb County in Alabama was the hardest hit, with 30 people dead there alone.
There are also fatalities in Arkansas, Georgia, Tennessee.
A witness to the tornado that hit Birmingham indicated it was at least a mile wide.
The mayor of Tuscaloosa described Tuscaloosa's infrastructure as 'decimated'.
80,000 chickens escaped as well.
The Weather Centre holds people affected in our thoughts and prayers today.
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