Snowfall

Snowfall is a type of precipitation in which snowflakes fall from the sky and accumulate on the ground. It typically occurs when the temperature is cold enough for the water vapor in the air to freeze into ice crystals, which then fall to the ground and form a layer of snow.

Snowfall can vary in intensity and duration, ranging from light and intermittent flurries to heavy and continuous snowstorms. It can occur at any time of year, but it is most common in areas with cold winters.

Snowfall is often accompanied by cold temperatures, strong winds, and low visibility, and it can significantly impact transportation, agriculture, and other aspects of daily life.

Snowfall

Climate Change Indicators: Snowfall

This indicator uses two metrics to show snowfall changes in the 48 contiguous states.

Figure 1.
 Change in Total Snowfall in the Contiguous 48 States, 1930–2007
This figure shows the average rate of change in total snowfall from 1930 to 2007 at 419 weather stations in the 48 contiguous states. Blue circles represent increased snowfall; red circles represent a fall.

Figure 2.
 Change in Snow-to-Precipitation Ratio in the Contiguous 48 States, 1949–2020
This figure shows the percent change in winter snow-to-fall ratio from 1949 to 2020 at 177 weather stations in the 48 contiguous states. This ratio measures what percentage of total winter precipitation falls from snow.

A decrease indicates that more precipitation falls in the rain rather than snow. Solid-colored circles represent stations where the trend is statistically significant.

State Latitude Longitude Percent change, 1949-2015 Significant (1 = sig, 0 = non-sig)
CA 39.1678 -120.143 -1.42 0
CA 41.7031 -122.641 -14.7964 1
CO 38.8575 -102.333 8.3354 0
CO 37.9492 -107.874 1.7537 0
CO 38.0383 -103.695 0.8449 0
CO 37.6911 -106.308 0 0
CO 37.7494 -107.095 0 0
CO 39.9919 -105.267 -0.852 0
CO 39.6261 -106.035 -1.3845 1
CO 40.5764 -105.086 -5.9995 1
CO 38.0636 -103.215 -16.898 1
CO 38.0517 -102.132 -18.5168 1
CO 38.0936 -102.631 -21.9319 1
IA 41.7947 -90.2639 3.5074 0
IA 41.0656 -92.7867 -0.9301 0
IA 41.0211 -91.9553 -2.556 0
IA 43.0603 -92.6717 -7.2349 0
IA 41.2825 -91.7078 -8.7046 0
IA 42.0356 -92.5806 -9.8832 0
IA 40.7244 -95.0192 -11.1328 1
IA 43.0453 -92.3122 -11.1541 0
IA 42.8825 -91.8303 -14.1006 1
IA 41.8814 -92.2764 -17.3027 1
ID 42.1231 -111.313 -3.479 0
ID 46.7281 -116.956 -4.7357 0
ID 48.3511 -116.835 -13.6178 1
ID 42.2342 -113.898 -15.6129 1
IL 40.5839 -90.9686 9.6418 0
IL 42.0981 -89.9842 -9.0028 0
IL 39.7347 -90.1978 -12.7516 1
IL 40.0839 -88.2403 -13.135 1
IL 41.7803 -88.3092 -18.3677 1
IN 38.5528 -86.7944 -0.2485 0
IN 40.58 -85.6586 -2.1584 0
IN 39.7594 -87.2269 -5.964 0
KS 37.1942 -99.7633 -3.5784 0
KS 39.7772 -98.7783 -12.3753 1
KS 37.2733 -99.3289 -16.7702 0
KS 37.0308 -100.907 -17.0116 0
KS 39.1972 -96.5814 -17.2317 1
KS 38.8586 -99.3358 -20.9663 1
KS 39.7408 -99.8361 -21.1438 1
KS 38.3772 -97.6097 -23.2951 1
KS 37.9411 -101.249 -23.856 1
KS 39.8228 -100.516 -25.0133 1
KS 39.7675 -101.807 -40.2854 1
MA 42.2122 -71.1136 -1.136 0
MA 42.3861 -72.5375 -7.5047 0
MD 39.0303 -76.9314 6.1699 0
MD 39.4131 -79.4003 -2.3288 0
MD 38.7153 -76.1908 -4.9558 0
ME 44.6894 -70.1564 12.7374 1
ME 45.6603 -69.812 1.3135 0
ME 43.6497 -70.3003 -1.7608 0
MI 42.2981 -83.6639 14.91 1
MI 46.4656 -90.1892 1.7892 0
MI 45.7858 -88.0842 1.5762 0
MI 41.9622 -84.9925 -3.5358 0
MI 41.9353 -84.6411 -3.976 0
MI 43.7072 -85.4819 -11.4452 1
MN 45.59 -95.8744 1.8318 0
MN 45.8775 -93.3147 -4.6718 0
MN 47.2436 -93.4975 -5.2256 0
MN 45.1219 -95.9269 -7.5828 0
MN 44.8831 -93.2289 -9.23 0
MN 46.7053 -92.5239 -11.0831 1
MO 40.2394 -94.6833 0.9088 0
MO 37.3908 -93.9492 -9.5424 1
MT 47.8206 -112.192 5.0836 0
MT 45.4956 -110.559 -4.9913 0
MT 48.2138 -106.621 -9.443 1
MT 48.3042 -114.264 -16.4933 1
NE 40.3706 -95.7469 6.39 0
NE 41.0408 -96.3811 3.2589 0
NE 41.6681 -103.104 -4.3807 0
NE 41.4514 -97.7644 -9.6418 0
NE 42.2619 -96.8636 -10.5364 0
NE 41.2453 -103.634 -11.0973 1
NE 42.5136 -99.0303 -13.3693 0
NE 40.3544 -96.1939 -13.9373 1
NE 40.0739 -97.1669 -16.0957 1
NE 41.4083 -99.675 -19.5463 1
NE 40.1306 -99.8278 -20.235 1
NE 40.6661 -96.1892 -24.6086 1
NE 40.6092 -96.8719 -25.9221 1
NE 40.4517 -99.3803 -27.7823 1
NE 40.175 -97.5903 -28.3148 1
NE 41.2789 -98.9697 -29.8981 1
NE 40.8997 -97.0908 -30.3667 1
NH 42.9389 -72.3247 -16.2235 1
NJ 39.7994 -74.7806 -3.1808 0
NV 40.8289 -115.789 -1.2567 0
NV 40.9017 -117.808 -1.3135 0
NV 40.6117 -116.892 -12.5883 0
NY 43.45 -76.5369 3.2589 0
NY 43.1167 -77.6767 2.3075 0
NY 42.3108 -78.0231 0.3053 0
NY 42.0997 -76.8358 -1.8602 0
NY 42.7167 -74.9267 -2.6909 0
NY 42.7431 -73.8092 -4.5156 0
NY 43.7928 -75.4828 -5.8859 0
NY 42.9486 -78.7369 -6.9012 0
NY 41.7681 -74.155 -7.3343 0
NY 42.4492 -76.4492 -7.8242 0
NY 43.1111 -76.1039 -10.1459 1
NY 42.1997 -75.985 -15.265 1
OH 41.2783 -84.3847 -3.7417 0
OR 42.8978 -122.134 -1.1715 0
OR 44.6342 -123.19 -3.4009 1
OR 43.7917 -123.028 -3.4577 1
OR 45.4486 -122.155 -6.39 1
OR 42.9508 -123.357 -7.5544 1
OR 45.3653 -119.564 -11.0405 1
PA 42.08 -80.1825 4.3523 0
PA 41.0147 -75.2072 -0.1491 0
PA 41.4197 -78.7492 -3.3512 0
PA 41.8467 -79.1494 -4.3239 0
PA 40.7933 -77.8672 -4.4304 0
PA 41.4003 -79.8306 -6.7947 0
PA 40.6508 -75.4492 -7.7532 0
PA 39.9353 -77.6394 -12.7445 1
PA 41.2433 -76.9217 -17.892 1
RI 41.4903 -71.5431 4.5014 0
RI 41.7219 -71.4325 -6.1415 0
SD 45.0469 -101.602 -1.3916 0
SD 43.6514 -97.7981 -3.6281 0
SD 43.9611 -101.861 -5.0126 0
SD 45.7656 -99.6222 -6.4894 0
SD 43.4894 -99.0628 -6.8302 0
SD 43.2358 -97.5714 -9.4217 0
SD 43.9025 -99.8583 -11.4807 0
SD 43.3111 -96.5878 -13.0995 0
SD 44.0683 -98.0833 -14.1219 1
SD 43.4378 -103.474 -15.5632 1
SD 42.7625 -96.9194 -29.2946 1
UT 41.525 -111.149 15.3857 1
UT 41.8253 -111.321 8.6975 0
UT 37.4403 -112.482 4.7144 0
UT 39.2872 -112.652 -1.491 0
UT 40.5353 -112.322 -2.3217 0
UT 39.2583 -111.631 -2.7051 0
UT 41.7456 -111.803 -3.2873 0
UT 37.0286 -112.536 -3.6991 0
UT 37.7686 -111.598 -6.4042 0
UT 37.6131 -109.485 -6.9438 0
UT 37.2092 -112.981 -14.484 1
UT 39.5608 -111.865 -35.1024 1
VA 37.2039 -80.4144 6.674 0
VA 38.4547 -78.9353 -2.4353 0
VA 38.0328 -78.5225 -3.9973 0
VA 37.7767 -79.4386 -5.9782 0
VT 44.42 -72.0194 9.4927 1
VT 44.4683 -73.15 -2.5205 0
WA 48.3508 -120.726 -5.7368 0
WA 47.4289 -120.31 -7.81 0
WA 47.4144 -121.756 -11.715 1
WA 47.6217 -117.528 -12.9078 1
WA 47.6575 -118.161 -14.5408 1
WI 45.8236 -91.8761 10.4867 0
WI 44.5378 -90.535 9.9045 0
WI 44.6411 -90.1333 5.6374 0
WI 45.8864 -89.7322 4.0683 0
WI 43.5594 -90.8761 -4.0044 0
WI 44.8919 -87.955 -4.0896 0
WI 43.0722 -88.0294 -11.2748 0
WI 42.7022 -87.7861 -13.6817 1
WI 43.5306 -89.4369 -14.5337 1
WI 44.0206 -88.5578 -14.5834 1
WI 42.8278 -90.7889 -15.2011 1
WI 43.7953 -88.4533 -15.975 1
WI 43.1742 -88.7364 -19.4114 1
WV 38.9803 -80.22 -15.8472 1
WY 42.1106 -104.949 3.6494 0
WY 43.7728 -111.034 1.6543 0
WY 41.7594 -104.822 1.1502 0
WY 44.3797 -108.035 0.3621 0
WY 41.1519 -104.806 -1.4839 0

Figure 2. Change in Snow-to-Precipitation Ratio in the Contiguous 48 States, 1949-2020
Data source: NOAA, 2021
Web update: April 2021
Units: degrees; degrees; percent change

Key Points

  • Total snowfall has declined in many parts of the country since general observations were made in 1930, with 57 percent of stations falling (see Figure 1).

    The average variation among all stations shown is a reduction of 0.19 percent per year.
  • In addition to changing the overall precipitation rate, climate change can also cause changes in precipitation type. One reason for the decrease in total snowfall is that more winter precipitation falls in the rain rather than snow.

    About 80 percent of stations in the adjacent 48 states experienced a drop in rainfall that fell as snow (see Figure 2).
  • Snowfall trends vary by region. The Pacific Northwest has seen a decline in total snowfall and the rate of precipitation that falls as snow.

    Parts of the Midwest also experienced a decline, particularly in snow-to-snowfall. Modest increases were seen in a few areas near the Great Lakes, which received more snow than in the past (see Figures 1 and 2).

Background

  1. Snowfall is an essential aspect of winter in most of the United States. Many people, including millions in the western United States, where snowmelt provides 75 percent of their water supply, rely on snow to provide water when the spring melts.

    Many communities also rely on snow for their winter recreation. Some plants and animals also depend on the melting of land and snow for survival.

    The snow falling on a given area directly affects the snow cover and the snowpack, which refers to the snow accumulated on the ground.

  2. Higher temperatures cause more water to evaporate from the land and oceans, leading to more precipitation, more giant storms, and, in some areas, greater precipitation diversity.

    A warmer climate causes more precipitation to fall in the rain than snow. But some places may see more snowfall if temperatures rise but stay below freezing or if storm tracks change.

    Areas near large lakes may also experience more snowfall as the lakes remain frozen longer, allowing more water to evaporate. In contrast, other regions may experience less snowfall due to winter droughts.

  3. Changes in the amount and timing of snowfall can affect the spawning of fish in the spring and the amount of water available to humans in the spring and summer.

    Changes in snowfall can also affect winter recreational activities such as skiing and the communities that rely on these activities.

About the Indicator

  • This indicator monitors the total snowfall and the percentage of precipitation that falls in the form of snow and rain. This data was collected from hundreds of weather stations in the 48 contiguous states.

  • Total snowfall is determined by the height of snow accumulated each day. These measured values ​​often appear in weather reports.

    Figure 1 shows how snowfall accumulation totals changed between 1930 and 2007 at more than 400 weather stations. These stations were chosen because they had high-quality data all this time.

    The EPA continues to work to identify an appropriate method of analysis to update this indicator.

  • Figure 2 shows trends in the overall rate of precipitation falling in the form of snow in each winter season.

    This is called the “snow-to-precipitation” ratio and is based on the amount of snow falling each year compared to the total amount of precipitation.

    For this comparison, snow was converted to an equivalent amount of liquid water. These data are available from 1949 to 2020.

About the Data

Indicator Notes

  1. Various factors make it challenging to measure snowfall precisely. The snow accumulations shown in Figure 1 are based on measuring sticks.

    This measurement method is subject to wind effects, the surrounding environment, and human error. Similarly, snow gauges in Figure 2 may capture less snow than rain due to the impact of wind.

    However, steps have been taken to limit this indicator to weather stations with the most consistent methods and highest quality data. As a result, some areas of the country have a higher station density than others.

  2. Both figures are limited to the winter season. Figure 1 comes from the snowfall analysis from October to May, while Figure 2 covers the months of November to March.

    Although these months account for the majority of snowfall in most areas, this indicator may not represent the snow season in some areas.

    Most of the data for mountainous regions come from low altitudes, as this is where the weather stations are usually located.

Data Sources

This indicator shows trends based on two sets of weather records collected and maintained by the National Oceanic and Atmospheric Administration. Figure 1 is adapted from an analysis by Kunkel et al.

The Cooperative Observer Program is based on records from meteorological stations. Figure 2 is an updated version of a comment by Feng and Hu 6 using data from the Global Historical Climatology Network.

Weather 01852 - Lowell MA

moderate rain

47°

moderate rain

Feels like 46°
Sunrise/Sunset - 01852
Sunrise/Sunset

06:33/19:06

Temperature - 01852
High/Low

49°F

/

44°F

Humidity in 01852
Humidity

84%

Pressure
Pressure

1013 hPa

Visibility
Visibility

3 mi

Wind
Wind

3.44 mph