There’s a common misconception that the severity of a fire season depends on the snowpack of the previous winter and spring. This is only partly true. While snowpack does greatly affect the summer fire season, just as important is what kind of weather occurs after the snowpack has already melted.
The weather in June, July and August is vital to what fire season will look like in Western Montana. A great snowpack can still mean a very active fire season if the weather turns too hot and dry after it has already melted. Heavy spring rains don’t necessarily make for a safer fire season, as the plants that feed off the nurturing water can easily turn into greater fuel for fire if dried out by hot summer weather.
The worst-case scenario is a low snowpack followed by a hot and dry summer, while the best-case scenario is a great snowpack that slowly melts throughout the early summer followed by timely rains.
El Niño is back for the winter of 2015-2016, meaning we will have milder and drier-than-normal conditions across the Northern Rockies. El Niño occurs when the Pacific waters off the west coast of South America become abnormally warm. The water is typically cold in this season, and the difference sets off dominoes around the world. While the air above cold water is similarly cool and calm, the abnormal warm water of an El Niño warms the air above it as well. This warm water holds more moisture, which shifts weather patterns.
El Niño winters mean cooler and wetter weather for the southern half of the U.S., which is good news for drought-plagued California. But it’s bad news for the Pacific Northwest and Northern Rockies, which can anticipate the low rainfall and small snowpack that threaten a drier and more severe fire season.
Mark Heyka has been chief meteorologist at NBC Montana for 16 of the 32 years he has worked in broadcasting. He grew up on a Kansas farm and became interested in weather after he saw his first tornado when he was seven years old.