The Favored Areas for Wildfire on the Olympic Peninsula

The Bear Gulch Fire is still burning on the southeast side in the Olympics and has increased to about 4700 acres.

Its location, on the southeast side of the Olympics, is a meteorologically favored one for wildfire. 

 Consider a map of the historical fires around the Olympics (below).  

Most fires occur to the northeast, east, and southeast of the Olympics.     You will also note that the biggest fires (largest dots) are clustered on the southwest side of the barrier.  The recent Bear Gulch Fire is in the middle of this "favored" area.

Why?  Because this is in a rainshadow area downstream of the Olympics, an area much drier than the rainforest region on the western slopes.

I can demonstrate this by showing the average annual rainfall for the area (below).  While the western side has some of the greatest yearly totals in the U.S., with some locations receiving over 150 inches a year, the eastern side enjoys "only" 60-80 inches.    The western side is much cooler during the summer, and is often flooded by marine clouds and drizzle.  

Another contributing factor to fire growth in this area is the steep terrain slopes on the eastern side of the Olympics (see the topographic map below).    Fire growth is enhanced on slopes, as heated air and fire move upwards.   It is also far more difficult to fight fires in steep terrain.

The unusually dry summer has certainly contributed to the fire potential this year.

There is some good news about the current fire: significant rain and cooler temperatures are arriving this week.

Below is the latest model forecast of accumulated precipitation through Thursday at 5 PM.  The Olympic Mountains are going to be hit fairly hard with precipitation, with a good wetting over the Bear Gulch Fire.  

Should give fire crews real aid in getting this fire restrained.