On my frequent travels between Missouri and Colorado, I have often noticed that, following a snowstorm, the Wakeeney, Kansas, area receives more snow than areas to its west or east on I-70. Assuming this must represent an upslope phenomenon, a reflection of the local topography, I examined a map of the region after yesterday's journey reinforced my past observations.
In fact, Wakeeney sits on the east edge of the High Plains at the west end of a topographic wedge in which the elevation is gradually rising from east to west. A prominent ridge just south of Hays, Kansas, is an erosional remnant of the High Plains, dividing the watersheds of the Smoky Hill River, to its south, from that of Big Creek to its north. In similar fashion, though not as visible from I-70, another eastward extension of the High Plains divides the Big Creek watershed from that of the Saline River, to the north of that ridge. Both of these ridges merge near Wakeeney and the rolling terrain between them climbs from 2000 feet at Hays to about 2450 feet at Wakeeney, yielding an upslope terrain that concentrates its orographic precipitation near the latter city; this scenario develops whenever easterly winds sweep Gulf moisture westward toward the High Plains.
Upsloping air cools and condenses, dropping its cargo of rain or snow. Such orographic weather events are common along mountain ranges, producing vital snowpacks in many regions and moist, forested retreats in the "sky islands" of desert areas. The upsloping terrain near Wakeeney is repeated at many other sites across the Great Plains, where a series of escarpments produce stair-like transitions from the lower, tallgrass zone on the east to the higher, shortgrass ecosystem of the High Plains. In addition, similar escarpments border the High Plains to the north, west and south, yielding upslope funnels in those regions as well; examples include the Pine Ridge Escarpment of western Nebraska and the Palmer Divide in eastern Colorado.
