april 27, 2011 huntsville, al storms hit early and often

APRIL 27, 2011 HUNTSVILLE, AL

STORMS HIT EARLY AND OFTEN

Some key issues.Busy week of storms prior to the 27th.

Overlapping shifts overnight The morning line was more violent than forecast

Power outages from previous storms.Kids late start then early dismissal

Lost Station Radar and one NEXRAD radar. Relied on Radio Stations, the web and social media

STORMS HIT EARLY AND OFTEN

April 27, 2011

39 tornadoes touched down across our viewing area between 4am and 8pm. These tornadoes ranged in intensity from 70 mph to winds up to 210 mph. Two were rated EF5. Many lives were lost and power was out for a majority of the viewers for several days.

April 27, 2011

The last image from our Live Doppler Radar indicated 210 mph shear.

Doppler Velocity

April 27, 2011

We had three EF4 tornadoes on the ground at one time. Attenuation became a problem we had to deal with. Rotation developed rapidly with every storm. We couldn’t focus on any one particular storm very long.

April 27, 2011

Live Doppler 48 radar performed well until we had multiple storms. We had three EF4 tornadoes on the ground at one time. Due to the very heavy rainfall associated with other storms in the area we were not able to see some important details with the 250kw radar. This attenuation was not a new problem with this radar but a big problem with tornado detection with the cell in Lawrence County.

6 mesos at this time

Attenuation Problems

In this radar image you can see how the heavy rainfall occurring from Courtland to Decatur is not allowing the 250K watts of power with the C Band radar to see enough. The ½ mile wide tornado is located near the M in Moulton but you can barely pick it out. We used velocity a lot to determine where the rotation was.

Stratus Station Cameras

Until I saw this image of the monster tornado over Limestone County I was unaware of just how large this tornado was and how much damage it was capable of. This storm was moving at speeds of 65 to 70 mph. It was low to the ground and covered in debris.

Moving NE at 65-70mph

Looking in the same direction

24 hours later. The man in this house was thrown across the Highway. He survived.

Bethel Church

The Bethel Church located next to the Doppler Radar. 20 people survived in the basement as the EF4 tornado removed the first floor.

Live Doppler 48 Radar

The tower off in the distance.

Live Doppler 48 Radar

The base of the tower.

Live Doppler 48 Radar

Part of the radome landed about ¼ mile away.

1974 or 2011?

Disaster and Social Media

The morning QLCS left 250,000 of people without power in Alabama. For many, the primary source of information became smart phone weather apps, Facebook and Twitter. Real, personal interaction is vital.

Social Media: Before, During, After

In the days and weeks following the disaster, Twitter hashtags became a powerful tool for organizing relief efforts. #ALNeeds were matched with #ALHaves, bringing charitable donations to the areas and people where they were most needed.

Visuals Make It Real

Research into the public reaction to seeing a live tornado on air should continue. For many, radar is abstract, but a real, tangible image of a tornado needs no interpretation.