Winter Storm — Cleveland, Oklahoma

2011-02-01 · Cleveland, Oklahoma

Event narrative

Several COOP and CoCoRaHS observers measured between five and eight inches of snow across the county. Wind gusts over 45 mph also created considerable blowing and drifting of the snowfall, which reduced visibilities. Unfortunately, one fatality occurred in Moore as a result of a sledding accident. The event began during the evening hours of 1/31.

Wider weather episode

After a relatively quiet early winter, a dose of reality, in the form of a major, record-setting winter storm, affected all of Oklahoma from late on January 31 through February 1. Periods of heavy sleet and snow, combined with winds that gusted over 40 mph, disrupted travel and closed hundreds of schools and businesses. Snowfall totals reached over a foot in some places, with snow drifts reaching three to five foot depths. Temperatures plummeted into the single digits and lower teens, and wind chills fell well below zero. In fact, wind chill values fell below -25 degrees over parts of northwestern Oklahoma!

Several days before the event, one would have thought that these were the final days of winter and that spring would soon begin. Record high temperatures were common over a large area on the 28th and 29th of January, with readings well into the 70s.

Unfortunately, these warm, mild days came to an abrupt end as a strong cold front moved southward over the southern Great Plains on January 30th, reducing high temperatures to 30 to 40 degrees cooler than the previous day. Max temperatures only reached the 20s across northern Oklahoma, with highs in the 30s prevailing across the southern two-thirds of Oklahoma and into north Texas.

Late on January 29th, a strong storm system finally moved onshore over southern California. At the same time, an arctic cold front began its trek south through the northern Great Plains, with a strong surface high pressure building in behind it.

The freezing line at the surface slowly moved south during the day on the January 31st, lying across the northwest half of Oklahoma by sunset and then advancing quickly southeast. At the same time, the storm system was moving through New Mexico with increasing lift out ahead of it.

Thunderstorms, some containing heavy sleet, developed over parts of west Texas and moved northeast over northern Texas. By this time, some of precipitation was developing and moving over sub-freezing surface temperatures. The precipitation coverage expanded through the evening hours toward Lawton and Oklahoma City. Periods of heavy thunder-sleet, occasionally mixed with freezing rain and heavy snow, were reported up and down I-44 toward Oklahoma City by 10 pm, with a light glaze of ice developing on elevated surfaces, and sleet accumulations of 1 to 2 inches over some areas of central Oklahoma. By 1 AM, temperatures were at or below freezing over all but far southeast Oklahoma.

With the cold air deepening above the surface, the precipitation was falling as snow across western and northwest Oklahoma, with a mixture of sleet and snow over southwest and central Oklahoma, and northern Texas, and freezing rain and sleet over southern Oklahoma. By 4 AM, all but southeast Oklahoma was reporting snow, with moderate to heavy snow bands setting up over western and central Oklahoma. The temperatures also continued to fall, with temperatures ranging from near 10 degrees over northern Oklahoma, to the lower to middle 20s over southeast Oklahoma, and the teens in between.

The snowfall was moderate to heavy at times, with some areas from central into northeast Oklahoma reporting snowfall rates of 2-3 inches per hour. By sunrise, around 6 inches of snow had fallen from Norman and Oklahoma City northeast toward Shawnee and Chandler, and the heavy snow continued to fall in parts of central Oklahoma.

In addition to the snow, the winds gusted at 35 to 45 mph, and temperatures fell into the single digits and lower teens. Rush hour traffic was very slow going. Visibilities with the heavy snow and strong winds were falling below mile, resulting in numerous accidents and stalled automobiles. The wind chills became just as big an issue by this time, with wind chill values falling below -15 degrees.

By mid morning, the heaviest snow bands had pivoted into eastern Oklahoma, but areas of moderate snowfall were still moving east through western and central Oklahoma. These bands still produced snowfall rates of 1 inch per hour over central Oklahoma. The snow finally ended from west to east by early afternoon, but the wind speeds remained strong with frequent gusts over 40 mph still occurring. Even after the snowfall had ended, near blizzard conditions continued through the afternoon, which hindered snow removal on roadways, and slowed rescues from stalled cars and accidents.

Unfortunately, four deaths were reported as a result of the winter storm, with one death occurring in Moore, and three in Miami, OK. The Oklahoma Highway Patrol reported over 150 automobile accidents statewide, ten of which resulted in injuries. There were also over 460 motorist-related calls, mainly from people that had become stranded in their vehicles. The situation could have been worse, but schools and businesses had closed prior to the beginning of the winter storm, which kept traffic at a minimum for much of the day on February 1st. In addition, the winter storm mainly produced snow and sleet, and freezing rain was less widespread and fell in shorter durations. As a result, ice accumulations were kept at a minimum, reducing the number of power outages across Oklahoma.

Source: NOAA Storm Events Database, event_id 277279. Narrative written by the NWS forecast office that issued the report.