Rising Temps, Shrinking Snowpack Fuel Western Wildfires

[marmar]

Climate Central -- Wildfire trends in the West are clear: there are more large fires burning now than at any time in the past 40 years and the total area burned each year has also increased. To explore these trends, Climate Central has developed this interactive tool to illustrate how warming temperatures and changing spring snowpack influences fires each year.


[font size="1"]Western U.S. wildfires have increased dramatically since 1970. Years with warmer spring and summer temperatures and reduced spring snowpack tend to have the most fires.In the coming decades, more warming and shrinking snowpack in the West is expected to cause even more big fires. Source: Climate Central[/font]

In our 2012 report, Western Wildfires, we analyzed federal wildfire data stretching back to the 1970s to see how fires have changed in the American West. In some states, like Arizona and Idaho, the number of large fires burning each year has tripled or even quadrupled. And in other states, including California, Colorado, New Mexico, Nevada, and Wyoming, the number of large fires has doubled.

Over the same span, average spring and summer temperatures across 11 Western states have increased by more than 1.5°F, contributing to the higher fire risks. Spring temperatures in Arizona have warmed faster than any other state in the U.S., rising nearly 1°F per decade since 1970, which has likely played a key role in Arizona’s rapid increase in fires over the past two decades.

In addition, years with abnormally warm spring and summer temperatures tend to be years with more and bigger fires. For example, 2012 was the hottest spring and summer on record for Colorado, and the state also saw its second-highest number of large fires. ..............................(more)

The complete piece is at: http://www.bloomberg.com/news/2013-07-12/rising-temps-shrinking-snowpack-fuel-western-wildfires.html

[byeya]

1. In the southwest, the vegetation starts the year at its most moist and gets drier

the more you progress into summer and early fall(typically). It's the opposite in the east where vegetation usually gets moister as the year progresses.
Summer and fall fires in the west; spring wildfires in the east.
If the west experiences lower than normal snowpack and then has a hot and dry April and May the fire season will be a bad one. June is normally the driest month of the year in this region and then July and August supply thunderstorms which ignite most of the fires.