Winter Storm (Ice, Sleet, Snow)
Data Limitations
Long-term records are limited, as 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 Texas between November and March and are usually created by large low-pressure systems moving rapidly across the country. In Texas, ice storms and freezing rain 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; ~30-100+ 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 TX 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 ~120 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-length of interest on the top right side of the map. 2. Click on the county of interest for information on the maximum snowfall event on record for your selected time period. 3. A table below the map shows location (by county and station), date of event, and snowfall total details. Click the top of the right two columns to sort by date or value.
Ice Storm Climatology
(1948-2000) Changnon and Karl, 2003 (open access)These are static images within a scientific report. The analysis includes the average annual number of days with freezing rain (Fig. 2) and month of highest average number of freezing rain days (Fig. 9). Texas typically experiences 1-2 freezing rain events per year, most commonly in January.
To view, click on the Full Text tab and scroll to the bottom of the page where figures are located.
Climate Change Trends
Years consisting of a large number of snowfall days declined significantly across the southern U.S. between 1930 and 2007. Models suggest that the number of snowfall events will likely continue to decrease given overall atmospheric warming. Models also show that by mid-century there will generally be a northward shift of the rain, sleet, and snow dividing line across the central U.S. This shift will add to the complexity of determining precipitation type for winter events (rain, ice, or snow) in north Texas. Overall, the frequency of snowfall and freezing rain events is expected to decline with rising air temperatures (Nielsen-Gammon et al. 2021). Read more about future winter storms in Climate Change Science and Projection Resources.
Western TX: The Texas Panhandle has experienced the most snow in the state (Nielsen-Gammon et al. 2021). As mentioned above, the northward shift of the rain/wintry precipitation dividing line and warmer temperatures are expected to decrease the frequency of winter storms.
Central TX: North central Texas is another area with more frequent snow occurrence and the frequency decreases to the south (Nielsen-Gammon et al. 2021). Warmer temperatures in the future are expected to decrease the amount and frequency of snowfall. Freezing rain occurrence is more uncertain in the future but expected to decline too.
Eastern TX: Eastern Texas has experienced the lowest frequency in snow occurrence, especially along the coast and further south. However, northeast Texas has experienced the most freezing rain events in the state (Nielsen-Gammon et al. 2021). With warmer temperatures in the future, freezing rain may decrease but there is uncertainty in the future occurrence of the weather pattern associated with such events.