Alan Journet, The Applegater, Applegate Partnership & Watershed Council Insert, Spring 2017 (Not Avalable online)
Since the Applegate Valley straddles the Jackson and Josephine County line, it is reasonable to interpret climate trends and projections for the valley as a combination of those reported for the two counties. These fall into the following main categories:’
The recent temperature trend comprises a rise of about 1 to 1.5⁰F during the period 1950 – 2005. Projections of future climate conditions depend on what scenario of greenhouse gas emissions we follow globally. Since the current global behavior seems to be best reflected in the ‘Business As Usual’ scenario of a continued acceleration in fossil fuel use and emissions, the BAU option seems the most reasonable upon which to base expectations.
Following that scenario, the temperature in the Valley is likely to rise some 8 to 9⁰F above the 1950-2005 average by 2100. Accompanying this overall trend, we can expect a greater rise during summer and fall than winter and spring, with a substantial increase in the number of summer days over 100⁰F.
The recent past and future both suggest much variability in annual precipitation, but no overall increase or decrease. However, the seasonal pattern will likely change to wetter winters and dryer summers with rain falling in more heavy downpour and fewer light rainfall incidents.
The recent past has seen a reduction in snowpack – a trend which is expected to continue as precipitation falls at lower elevations as rain rather than higher as snow. By the end of the century, snow water accumulation could be as low as 10 – 20% of historical averages.
The date of spring snowmelt has been advancing and is expected to continue advancing. The result will be peak streamflow shifting earlier in the season and a depletion of late summer and fall streamflow as irrigation demand peaks, with generally warmer water promoting pathogens and compromising our iconic fish species.
Drought and Wildfire Potential:
As temperatures rise, snowpack dwindles, snowmelt advances, and summer rainfall drops, soil moisture will decrease further. The potential for both drought and enhanced wildfire risk is apparent in this projection.
For more information on Rogue Valley climate trends and projections, visit https://socan.eco/southern-oregon/