Winter Storm (Ice, Sleet, Snow)
Data Limitations
Ice storm/freezing rain data are very limited due to the complexity of observational accounts (e.g., rain, freezing rain, and snow can occur at a single station
during a single event).
Definition and Description
A winter storm is a winter weather event that produces impactful accumulations of freezing rain (ice), sleet, and/or snow (NWS 2018).
Winter storms may include heavy snowfall, blowing and drifting snow, high winds, extreme cold, or ice storms. Among the greatest hazards associated with winter storms are traffic accidents. The most extreme instance is a blizzard, which is defined as winds greater than 35 mph, visibility less than ¼ mile, lasting at least 3 hours. New snowfall is not necessary for a blizzard, and blowing snow can similarly obscure visibility.
Winter storms are measured by snowfall accumulation or ice thickness. Winter storms occur in Arkansas between November and March and are usually created by large low-pressure systems moving rapidly across the country. In Arkansas, ice storms are a greater threat than blizzards. Access to moisture from the Gulf of Mexico falling over shallow cold air near the surface can produce ice accumulations of two inches or greater with tremendous damage to power distribution.
Historical Data
Snowfall Climatology Toolbox
(Period of record varies by station; ~30- 140 years) Midwestern Regional Climate CenterThis interactive tool shows normal (1991-2020) annual and monthly snowfall, average annual number of days with snow totals at certain thresholds, average first and last snow date, and record 1-day snowfall. The map displays normal values while the graph below it shows the variable by year.
1. Position map to area of interest or choose AR in the State Selection drop-down menu on the right. 2. On the top of the screen, select a variable you’re interested in (e.g., Annual Snowfall). Some variables have options on the right side of the screen to select, such as a month to display for monthly snowfall or a snow threshold. 3. For most variables, the map displays the normal/average value for the variable you selected. For Record 1-Day Snowfall, it shows the record value at each point. The legend for the colored points is on the top-right side of the screen. 4. The graph below the map shows more details, such as the values per year instead of an average. Note: The map default shows stations with data from at least 1991- 2020. If you’d like to see longer time frames, you can move the slider under the Data Available Since option on the right. When you select a different start year, it will only show stations with available data.
Snowfall Extremes
(Period of record varies by location; up to ~140 years) NOAA National Centers for Environmental InformationThis interactive static map shows the 1-Day, 2-Day, and 3-Day snowfall maximums by county.
1. Select the day(s) of interest on the top right side of the map. 2. Mouse over county of interest for information on the maximum snowfall event on record. 3. A table below the map shows location (by county and station), date of event, and snowfall total details.
Ice Storm Climatology
(1948-2000) Changnon and Karl, 2003 (open access)These are static images within a scientific report. Shows the average annual number of days with freezing rain (Fig. 2) and month of highest average number of freezing rain days (Fig 9). For reference when viewing these figures, Arkansas typically sees 1-4 freezing rain events per year, most commonly in January.
To view, 1. Click on the Full Text tab and scroll to the bottom of the page. 2. View full sized images of Fig 2. and Fig. 9 by clicking on respective images.
Climate Change Trends
Years consisting of a large number of snowfall days declined across the southern United States between 1930 and 2007 (Easterling et al. 2017). Models suggest that although the number of snowfall events will likely continue to decrease given overall atmospheric warming, when snow does occur, accumulations will be greater due to increases in atmospheric moisture (Krasting et al. 2013). There is significant uncertainty surrounding the future of ice storms in Arkansas. Observational data limitations and the complexity of the events themselves make it difficult to determine with much specificity whether patterns have and/or will change. Models show that by mid-century there will generally be a northward shift of the rain, sleet, and snow dividing line across the central and eastern United States. This shift will add to the complexity of determining precipitation type for winter events (rain, ice or snow) in Arkansas, however, the increase in atmospheric moisture may bring an increase to the amount of precipitation that does fall (Easterling et al. 2017).