blackfoot-valley

The Climate Climatically, this area is classed by climatologists and geographers as transitional between humid continental and dry continental, the term “conti- nental” denoting large contrasts in temperature between summer and winter. Such seasonal contrast is true of the interiors of all large continents in the mid-latitudes; that is, lying between the tropic / subtropic zones and the polar regions. “Humid” in careful usage indicates a higher average of precipitation- rain and snow - than the potential rate of evaporation, thus giving rise to per- manent streams. Humid regions generally support forest as their dominant ground cover. The valley of Nevada Creek and this part of the Blackfoot’s course only barely, if at all qualifies as humid, being actually a transition area between humid and dry, as shown by the forested slopes (which intercept more precipi- tation), by the bunch grass and shrubs dominating the valley floor, and by the need for supplimental irrigation to insure sufficient forage for moderately large numbers of cattle here. Ovando, a few miles north of the Wales Ranch land, records an average yearly precipitation of 16 inches. (Judging from the veg- etation cover of the non-irrigated areas, it is probably somewhat less than the Ranch itself. One old-time resident of the Helmville area, Tom Geary, reports 15 inches as tops, but in any given year it’s usually 12 to 14 inches.) The wettest part of the year is in late spring. The wettest month is June with May close behind, both months getting around 2 inches of rain on the average. 36