Top Ten U.S. Weather Events Of 2012

by Jeff Masters, via the Wunderblog

It was another year of incredible weather extremes unparalleled in American history during 2012. Eleven billion-dollar weather disasters hit the U.S., a figure exceeded only by the fourteen such disasters during the equally insane weather year of 2011. I present for you now the top ten weather stories of 2012, chosen for their meteorological significance and human and economic impact.

Video 1. Hour-by-hour animation of infrared satellite images for 2012. The loop goes in slow-motion to feature such events as Hurricane Sandy, the June Derecho, Summer in March, and other top weather events of 2012. The date stamp is at lower left; you will want to make the animation full screen to see the date. Special thanks to wunderground’s Deb Mitchell for putting this together!

1) Superstorm Sandy
Hurricane Sandy was truly astounding in its size and power. At its peak size, twenty hours before landfall, Sandy had tropical storm-force winds that covered an area nearly one-fifth the area of the contiguous United States. Sandy’s area of ocean with twelve-foot seas peaked at 1.4 million square miles–nearly one-half the area of the contiguous United States, or 1% of Earth’s total ocean area. Most incredibly, ten hours before landfall (9:30 am EDT October 29), the total energy of Sandy’s winds of tropical storm-force and higher peaked at 329 terajoules–the highest value for any Atlantic hurricane since at least 1969, and equivalent to five Hiroshima-sized atomic bombs.

At landfall, Sandy’s tropical storm-force winds spanned 943 miles of the the U.S. coast. No hurricane on record has been larger. Sandy’s huge size prompted high wind warnings to be posted from Chicago to Eastern Maine, and from Michigan’s Upper Peninsula to Florida’s Lake Okeechobee–an area home to 120 million people. Sandy’s winds simultaneously caused damage to buildings on the shores of Lake Michigan at Indiana Dunes National Lake Shore, and toppled power lines in Nova Scotia, Canada–locations 1200 miles apart!

Sandy made landfall near Atlantic City, NJ on October 29, with sustained winds of 80 mph and a central minimum pressure of 946 mb–the lowest pressure on record along the Northeast coast. The Battery, in New York City Harbor, had an observed water level of 13.88 feet, besting the previous record set by Hurricane Donna in 1960 by 3 feet. Sandy also brought torrential rainfall to the Mid-Atlantic, with over 12 inches of rain observed in parts of Maryland. In addition, Sandy generated blizzard conditions for the central and southern Appalachians with more than a foot of snow falling in six states from North Carolina to Pennsylvania, shattering October snow records. Over 130 fatalities were reported and over 8.5 million customers lost power–the second largest weather-related power outage in U.S. history, behind the 10 million that lost power during the Blizzard of 1993. Damage from Sandy is estimated at $62 billion.

Figure 1. Cabs lie flooded on October 30, 2012, in Hoboken, NJ, in the wake of Hurricane Sandy. AP photo: Charles Sykes.

2) Warmest Year on Record
Spring, March, July, and the annual temperature were all warmest on record in the contiguous U.S. July was the warmest month of any month in the 1,400+ months of the U.S. data record, going back to 1895. The spring temperature departure from average was the largest on record for any season, and March temperatures had the second largest warm departure from average of any month in U.S. history. All-time hottest temperature records were set over approximately 7% of the area of the contiguous U.S., according to a database of 298 major U.S. cities maintained by wunderground’s weather historian, Christopher C. Burt. Given the very warm December temperatures so far, the final 2012 annual temperature is likely to break the previous warmest year on record (1998) by at least 0.7°F–a colossal margin to break an annual record by. It is likely that 15 states will end up with their warmest year on record in 2012, and 42 states will have a top-ten warmest year.

Figure 2. One of 2012′s incredibly hot days: high temperatures on August 1 in Oklahoma from the Oklahoma Mesonet. It was the hottest day in Oklahoma since August 1936, with more than half of the state recording temperatures of 110° or higher. Oklahoma City hit 112°, tied for the city’s 3nd highest temperature since record keeping began in 1890. The only hotter days occurred two days later–on August 3, 2012–and back on August 11, 1936 (113°.)

3) The Great Drought of 2012
The Great U.S. Drought of 2012 may well turn out to be the biggest weather story of 2012, since its full impacts have not yet been realized. The area of the contiguous U.S. in moderate or greater drought peaked at 61.8% in July–the largest such area since the Dust Bowl drought of December 1939. The heat and dryness resulted in record or near-record evaporation rates, causing major impact on corn, soybean and wheat belts in addition to livestock production. Drought upstream of the Lower Mississippi River caused record and near-record low stream flows along the river in Mississippi and Louisiana, resulting in limited river transportation and commerce. Crop damages alone from the great drought are estimated at $35 billion. As the total scope of losses is realized across all lines of business in coming months, this number will climb significantly.

Figure 3. Corn in Colby, Kansas withers in the Great Drought of 2012 on May 27. Image credit: Wunderphotographer treeman.

4) Wildfire Season of 2012
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