Kansas climate patterns: Earliest snowfall and first snowfall dates since 1950
The recent snow that fell across Kansas was a topic of conversation around the Department of Agronomy this week. It is interesting that this early snowfall event was across a majority of Kansas (Figure 1) and was the first snowfall event for many areas. “First snowfall” is defined as the first occurrence of 24-hour snowfall (daily) accumulation of 0.1 inches or greater. Here we used the global historical climatology network data set from 1950 to 2018. Please note that 2018 is incomplete so this analysis is limited to 1950 to 2017.
Our analysis is based on the following assumptions:
- A year was considered as missing if this station contains more than 20 days missing (5% of 365 days) in a year.
- A station was selected in this analysis when it has at least 50 years data of available first snowfall dates between 1950 and 2017.
Using the assumptions above, 15 stations were selected across Kansas to show the earliest snowfall dates and the first snowfall dates from 1950 to 2017.
Figure 1. Snowfall events dated on October 14, 2018 in Colby, western Kansas (left) and Manhattan, eastern Kansas (right). The photos were taken by Dr. Rob Aiken and Dr. Guihua Bai.
The earliest snowfall dates ranged from September 21 in northwest Kansas to November 8 in southeast Kansas. This diagonal upward pattern of earliest snowfall date is consistent with the average annual snowfall depths (i.e. climatology snowfall depth across Kansas). Compared to historical records shown in Figure 2, the first snowfall event, that occurred last weekend in Kansas, was relatively early for eastern Kansas. However, this was not the case for central and western Kansas.
Figure 2. Earliest snowfall dates across Kansas from 1950 to 2017 for 15 select stations.
Three stations (eastern, central, and western Kansas) are highlighted to examine the first snowfall dates across Kansas (Figure 3). Figure 3 shows a time series of the first snowfall event in Manhattan, Hays, and Scott City, respectively. The result shows that there is approximate a weeklong gradient in the average first snowfall dates from eastern Kansas, central Kansas, to western Kansas. The average first snowfall dates are December 12 (Manhattan), December 6 (Hays), and November 27 (Scott City). It should be noted that this result was not mainly attributed by physical latitudes (Figure. 2) but perhaps more by moisture and storm circulation patterns in the Kansas atmosphere.
Figure 3. Time series of first snowfall dates in (a) Manhattan, (b) Hays, and (c) Scott City from 1950 to 2017. First snowfall events that lie within the shaded areas are events that occurred after the beginning of a new year (i.e. in January or February).
If you are interested in additional information about Kansas Climate, including the latest weekly and monthly snowfall totals, check out the website: http://climate.k-state.edu
Xiaomao Lin, State Climatologist
Gerard Kluitenberg, Soil and Environmental Physics
Rob Aiken, Crop Research Scientist, Northwest Research-Extension Center, Colby