Drought and extreme heat fuel wildfires in U.S. West
Friday, July 13, 2018, 16:00 - Severe to exceptional drought conditions in combination with above normal heat across the U.S. West are helping wildfires burn out of control across a dozen states.
2018 has already seen over 3.3 million acres of forested areas burn in the U.S., a value slightly lower than the one registered this time last year. Last year saw 10 million acres burn away, making it the second worst year on record.
Fires have been devastating over the past few weeks, burning large sections of Colorado, Utah, New Mexico and California. Two key factors are fueling the blazes: a persistent drought that is affecting most of the southwest since last year, and the heat dome that has been impacting much of the western U.S. since late last week. It does not take much for fires to ignite and rapidly spread as the vegetation in these areas is so dry.
Despite the summer monsoon rains that have been affecting the Four Corner states over the past week, conditions remain dry. However, they are expected to improve as the summer progresses.
Very dry areas of New Mexico, Arizona, Colorado and Utah will see fire weather conditions decrease. Although currently, lightning from some of the dry thunderstorms that move through the region is capable of starting fires, which together with gusty winds can spread rapidly.
Over the next three days, the forecast calls for much needed rain in areas of the southwest and the central Rockies where wildfires are currently out of control. Even some mountain areas of eastern California could see rain in the coming days.
The main problem with summer monsoon rains is that they come with thunder, meaning gusty winds are normally part of the deal. The good part, however, is that water is always welcomed by firefighters even though the precipitation produced by these thunderstorms tends to be spotty and short lived.
Between this Friday and Saturday, critical fire weather is expected mainly across central Oregon and Washington. Overall, the July wildfire outlook calls for above normal wildland fire potential (see below) across much of the Western U.S. States such as Utah, Idaho, California, Nevada, Oregon and Washington could see the worst fire conditions.
August looks very similar, with less potential across Utah, but an increase across many areas of Montana. The good news is that the summer monsoon rains should help erase potential fire conditions over much of the southwest.
What is really driving the wildfires this year is the exceptional drought that extends across large areas of Utah, Colorado, New Mexico and Arizona. Conditions like the ones we are seeing this year in the past used to occur every four to five decades. However, today, they are becoming more frequent and extend over larger areas.
Rising average temperatures and extreme heat episodes are also contributing to the new fire scenario, and on top of the natural elements, forests are becoming less healthy compared to the past. Fire needs fuel to burn, and there is a lot of that in the west. Since the 1950s the U.S. government pursued a fire suppression policy that sharply reduced the acreage burned, but caused forests to become choked with underbrush and trees, allowing invasive species to enter. Such is the case in the southwest, where bark beetles have overtaken conifers, allowing wildfires to burn non-stop.