The idea that California’s heavy rainfall this year will lower the likeliness of wildfires does not appear to be entirely true, according to a new study. A study published in the Proceedings of the National Academy of Science shows that wildfires are a product of higher temperatures caused by climate change and the dangerous years of build-up of forest fuel from fire suppression.
-
The study examines how the Pacific jet stream affects fire season. Looking at data from the last 400 years, they found that when the high altitude winds that carry wet weather is over California have resulted in a wet winter, and when it is not, it causes high fire activity. However, the links seem to have disappeared by 1977. For example in 2017, one of California’s wettest winters, when over 200,000 acres burned across wine country, killing 41 people.
-
The change appears to be caused by a combination of two factors. Inadvertently building overgrown forests since the early 1900s, due to a greater effort to extinguish wildfires in combination with climate change, are the primary suspects. With hotter and more arid weather drying out wildlands and creating forest fuels, even a wet winter can now result in a severe fire season the next summer.
-
The historical record of the jet stream since 1600 was derived from combining existing climate reconstructions with their own modeling based on tree ring data, and comparing it to the intensity of California’s fire seasons via tree ring information and fire scars.
-
These findings show a greater need for policy makers to address climate change and for firefighters to deal with the unnatural buildup of vegetation. This can be seen by the fact that even though California is currently having an unusually wet winter, the National Interagency Fire Center, in its initial forecast, still projects a high wildfire potential for the state.
