Top U.S. weather event of 2010: Snowmageddon

As we ring in the new year, it's time to look back on 2010 and reflect upon what a remarkable weather year it was. Today, I'll focus on the U.S. While 2010 certainly had its share of violent and destructive weather events in the U.S., I am thankful for two things:

1) The sustained period of northerly winds needed to blow oil from the Deepwater Horizon catastrophe into the Loop Current never materialized, and the Florida Keys and U.S. East Coast were spared oil damage.

2) The 3rd busiest Atlantic hurricane season on record resulted in minimal damage to the U.S., with only one minimum strength tropical storm (Bonnie) making direct landfall in the U.S.

Here, then, is my list of the top three most significant weather events in the U.S. in 2010:

#1: Snowmageddon
The top U.S. weather story of 2010 has to be "Snowmageddon", the remarkable February blizzard that buried the mid-Atlantic under 2 - 3 feet of snow. Snowmageddon set the all-time record for heaviest snowfall in Delaware history, thanks to the 26.5" that fell in Wilmington (old state record: 25" in the President's Day storm of 2003). "Snowmageddon" dumped the second heaviest at Philadelphia 28.5"), second heaviest at Atlantic City (18.2"), third heaviest at Baltimore (24.8"), and the 4th heaviest at Washington D.C. (17.8"). Several locations in Maryland saw over three feet of snow, with the northern Washington D.C. suburb of Colesville receiving 40", and the southern Baltimore suburb of Elkridge receiving 38.3". While the blizzard was not an exceptionally strong storm--the central pressure was a rather unimpressive 986 mb at the height of the blizzard--it was an exceptionally wet storm. The melted equivalent precipitation for the blizzard exceeded three inches along its core snow belt. That's an phenomenal amount of moisture for a winter storm. The blizzard formed a very unstable region aloft where thunderstorms were able to build, and there were many reports of thundersnow during the height of the storm. These embedded thunderstorms were able to generate very heavy snow bursts of 2 - 3 inches per hour.

"Snowmageddon" was followed just three days later by a second massive snowstorm which dumped another 1 - 2 feet of snow on the mid-Atlantic. By the time the flakes stopped flying, Washington D.C., Philadelphia, Wilmington, and Atlantic City all had their snowiest winters on record. The February snowstorms killed 41 people and did up to $2.4 billion in damage, according to the Insurance Information Institute.


Figure 1. There's a car under here somewhere! Maryland resident digs out after Snowmageddon. Image credit: wunderphotographer chills.

#2: The Tennessee and Nashville floods
An atmospheric river of moisture originating in the East Pacific subtropics surged northwards into the southeast U.S. during the first two days of May, unleashing unprecedented rains that caused a 1000-year flood in Tennessee, Kentucky, and northern Mississippi. The floods killed 31 people, making it the deadliest non-tropical storm or hurricane flood disaster in the U.S. since the October 1998 Central Texas floods that killed 31 when a cold front stalled over Texas. The 2010 flood did more than $1.5 billion in damage, much of it in Nashville, Tennessee, where ten fatalities were reported. The city had its heaviest 1-day and 2-day rainfall amounts in its history. A remarkable 7.25" of rain fell on May 2, breaking the record for most rain in a single day (6.60", set September 13, 1979.) Nashville's third greatest day of rainfall on record occurred on May 1, 2010, when 6.32" fell. Nashville also eclipsed its greatest 6-hour and 12-hour rainfall events on record during the May 2 deluge, with 5.57" and 7.20", respectively. By the end of May 2, it was already the rainiest May in Nashville's history. Rainfall records were smashed all across Tennessee and Kentucky, with amounts as high as 17.73" recorded at Camden, TN, and 17.02" at Brownsville, TN. According to Christopher C. Burt, the author of the excellent book Extreme Weather, the 13.30" that fell on Camden in 24 hours just missed eclipsing the state's all-time 24-hour precipitation record, the 13.60" inches that fell on Milan on September 13, 1982.


Figure 2. Parking via Mother Nature. A scene in Nashville after the May, 2010 flood. Image credit: wunderphotographer jannash.

#3: May 10 tornado outbreak
On May 10, a massive tornado outbreak affected large areas of Oklahoma, Kansas, and Missouri, with the bulk of the activity in central and eastern Oklahoma. Over 60 tornadoes, including two violent EF-4 twisters and six strong EF-3s, hit the region. The tornadoes and associated severe thunderstorms caused approximately $2 billion in damage, according to Swiss Re Insurance Company. The most destructive tornadoes caused severe damage in southern suburbs of the Oklahoma City metropolitan area and just east of Norman, Oklahoma. Three people were killed by the tornadoes.


Figure 3. Video of the May 10, 2010 tornado near Norman, OK. Dr. Rob Carver's blog has many more videos from this spectacular outbreak linked.

I'll be back with a new post on Friday.

Our extreme weather blogger, Christopher C. Burt, has an interesting post on historic episodes where large numbers of dead birds have fallen from the sky.

Jeff Masters