Frozen soils prevented the infiltration of rain or snowmelt. In some cases runoff equaled total water added by either rain or snowmelt. Although these data were collected from a limited period during one winter, they are indicative of the erosion process in the dryland Northwest. Air temperatures had averaged 23 F for the previous week. A warm moist air mass entered the area about 11 p.m. on Jan. 11.
Condensation adds a small amount of water, but more importantly it adds heat.
As water condenses it gives up heat. Heat given up by condensation on a snowpack accelerates snowmelt. 0.4 4.7 0.3 Gilliam 4 2.5 6.0 13.2 Morrow 2 0.3 5.2 0.5 l Cumulative precipitation from December 1 to February 25. No runoff observed until January 12. Clearly frozen soils play a key role in the erosion process.