Rain fuels fire

Does Heavy Rain Actually Fuel Wildfires?

It may seem contradictory, but the recent drought-quenching rains seen across much of the west may actually lead to a higher potential for wildfires.  Thus far, 2017 has brought severe winter storms and record rainfall. These drenching rains have been a welcome respite to many areas suffering from multi-year drought conditions.  The excess water, however, has also brought flooding, landslides and the potential for increased wildfire risk.

Fine Fuel Growth

In areas that have experienced prolonged drought conditions or recent wildfires, rains often lead to an explosive growth of new vegetation.  Much of this vegetation growth is in the form of native and non-native grasses. Moist fuels are an ideal fire retardant, but these grasses are very susceptible to drying out after just a short period of low humidity and high temperatures. Once dried, these “fine fuels” are easy to ignite. Something as small as an errant cigarette butt or a spark from a vehicle tail pipe is a sufficient catalyst to spark a wildfire. Once active, these wildfires can move rapidly and are prone to “spotting”. Spotting occurs when embers are blown to nearby fuels and cause multiple ignitions, making the wildfire difficult to contain.

Rain fuels fire

Rapidly Spreading Fire in Fine Fuels.

Preparation

The ease with which these fine fuels can quickly dry and lead to hazardous conditions is one of the main factors fire managers consider when scheduling prescribed burns. Firefighters use prescribed burns to reduce the build up of fine fuels, thus decreasing the risk for wildfires in the future. Prescribed burns can also be used to establish fire breaks so that a small fire doesn’t become unmanageable. Individual homeowners can help with fire mitigation efforts by mowing grasses around their property and creating a defensible space.

Weather Outlook

Few meteorologists predicted the unprecedented rainfall that has impacted the majority of the United States so far this year. The recent storms have saturated fuels, likely delaying the onset of fire season. The threat, however, will not be all together eliminated. Long range weather predictions are vague at best. The Old Farmer’s Almanac suggests that the majority of the United States should see a hotter, but wetter than normal summer. The National Interagency Fire Center is also somewhat optimistic, predicting a delay of fire season until at least June. It remains to be seen if the recent storms will be enough to help combat the increasingly hot summers and severity of recent wildfires.

Sources

https://www.firescience.gov/projects/05-2-1-13/project/05-2-1-13_05-2-1-13_JFSP_Final_Report_05-2-1-13.pdf

https://www.fs.fed.us/fire/management/rx.html

http://hppr.org/post/last-years-rains-bring-increased-fire-risk-2017

http://www.auburn.edu/academic/forestry_wildlife/fire/fuels_effect.htm

http://www.canberratimes.com.au/act-news/heavy-spring-rain-has-boosted-fuel-loads-ahead-of-fire-season-20161023-gs8jvy.html

1 reply

Trackbacks & Pingbacks

  1. […] High winds with dry fuels and low RH; despite last winter’s drought-relieving rains, the excess fine fuels were ripe for the taking. The multiple starts knocked out cell towers and power across the area. […]

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply