Friday, December 30, 2011

2011 ... a frightening weather year

The final months of 2011 produced little in the way of weather news, but the tone for this year was set early in the year, and it was not good.

One of the highest tornado death tolls in recent memory and a devastating drought in parts of the South and Southwest were the big stories of the year. But there also were memorable snowstorms in the East, Southeast and Midwest, plus major spring flooding in the Midwest and South.

Summer didn't bring an end to the misery, with a 40-state heat wave in July and a hurricane that produced major flooding in late August.

Five people were killed in November tornadoes in the Carolinas, pushing the twister death toll this year in the country to near 500.

And the news wasn't limited to the continental United States. A storm of epic proportions hit the west coast of Alaska in November.

The year started with a Greenland block -- strong high pressure over Greenland that caused a Negative Arctic Oscillation and brought repeated bouts of cold weather to the East and Midwest. Storm systems formed along the edge of the circulation flow and brought heavy snow to the East.

In mid-February, the Greenland block weakened. With La Nina conditions, the persistent storm track brought several rounds of tornadoes to the South and Midwest.

Summer of 2011 was extremely hot. The storm track moved a bit north, and the result was a very wet season for the eastern Great Lakes and Northeast -- and a very dry summer elsewhere.

The hurricane season was, for the United States, a washout. Only one storm of note affected the country.

I'll recap Charlotte-area 2011 weather later this weekend, but here's a look at the big meteorological stories in the country for the year:

JANUARY SNOW ... A series of snowstorms hit the eastern United States in January. The first brought snow to the Carolinas around Jan. 9, and it moved up the coast. On Jan. 11, every state except Florida had snow on the ground somewhere.

Huntsville, Ala., had snow on the ground for eight straight days, setting a record. New York City and Hartford broke January snowfall records, and South Bend, Ind., set a 24-hour snowfall record with 26 inches on Jan. 8.

At the tail end of the month (actually stretching to Feb. 3) came a Midwest storm. Blizzard conditions, with two feet of snow, were reported in Chicago.

TORNADOES ... The jet stream set up a pattern for storms in April and May, with the track stretching from Texas across Tennessee and Kentucky. That put states from Missouri to the Carolinas in the danger zone for severe weather.

A tornado outbreak in the Carolinas and elsewhere in the Southeast killed 38 people April 14-16, but that was a prelude for the worst of it -- the April 25-28 tornadoes that killed 321 people. Tuscaloosa, Ala., was among the hardest-hit cities. Another outbreak, around May 22-24, included an F5 tornado in Joplin, Mo. The death toll was 177.

Then came the Nov. 16 tornadoes in the Carolinas, with three deaths in Rock Hill and two in Davidson County.

Probably the biggest impact from 2011's tornadoes is a fresh look at the warning system in the United States. A National Weather Service study on the Joplin twister showed that many people did not pay attention to tornado warnings issued by the Weather Service. Emergency management officials will spend 2012 trying to determine why -- and how to change this.

FLOODING ... Extremely heavy rainfall in late April and early May brought record flooding along parts of the Ohio and Mississippi rivers. The area below St. Louis, stretching down to Vicksburg, Miss., was especially hard-hit. But there also was severe flooding during the spring on the Souris River, near Minot, N.D.

JULY HEAT ... Temperatures regularly soared above 100 degrees in much of the South and Southwest, with places like Dallas and Austin shattering records for consecutive 100-degree days. Readings of 100 degrees or more were recorded in Austin and San Antonio as late as the end of September.

At least 40 states reported heat wave conditions. In the Carolinas and other parts of the Southeast, the humidity was a big story. While record heat was not a problem, the high humidity kept temperatures from falling below the mid 70s many nights from late June to mid August.

DROUGHT AND WILDFIRES ... The driest conditions in history were reported across all or parts of Texas, Oklahoma, Arkansas, Louisiana, Kansas, New Mexico, Arizona and Colorado. A lesser area of drought affected a corridor from Mississippi, across Alabama, Georgia and western South Carolina.

As might be expected, wildfires were a huge problem. Fires caused more than $1 billion damage in Texas, New Mexico and Arizona. The Bastrop fire, about 30 miles southeast of Austin, destroyed 1,500 homes and was the worst wildfire in Texas history.

ON THE OTHER HAND ... While part of the country was baking, another part was having a record wet year. Storm systems repeatedly crossed an area from Indiana, over Ohio, Pennsylvania, New York and New England. Then rain from Hurricane Irene added to the mess. The result was several episodes of flooding and some record amounts of precipitation for the year.

Philadelphia had more rain this year (64 1/2 inches) than did Bangkok, Thailand (59 inches).

HURRICANE IRENE ... It was the only hurricane to make landfall in the United States this year, but Irene left its mark. The storm first touched U.S. soil in North Carolina, carving a path slightly inland from the Outer Banks and causing major damage from Morehead City north to the Virginia line.

Irene's approach caused hurricane warnings to be issued for New York City, for the first time in many years. But the system weakened to tropical storm status before making a second U.S. landfall on Long Island. However, heavy rain from Irene's remnants caused massive flooding in Pennsylvania, New Jersey, New York, Connecticut and Vermont. Millions of people were without power for weeks.

ALASKA STORM ... The Bering Sea Superstorm of Nov. 8-9 had low pressure equal to that of a Category 3 hurricane, and it heavily damaged 40 villages and cities along Alaska's west coast. Carrying 100 mph winds, the storm created a 10-foot surge near Nome, and it produced incredible blizzard conditions with heavy snow, gigantic waves, and hurricane-force winds. Advance warning paid off, though, as only one life was claimed by the storm.