Fire danger in the Eastern Sierra has eased somewhat following an unusually wet August, but that doesn’t mean it is time to relax.
According to fire officials, September can be one of the warmest and driest months. If that pattern holds, it could erase much of the gains made in August, when almost three weeks of heavy rain took the sharp edge off the drought.
“We are not out of the woods, yet,” said Jeff Iler, the fire management officer for the Inyo National Forest and the Bishop Bureau of Land Management field office. But a strong monsoon moisture pattern that moved into the Central Sierra region in August has made a big difference.
“We are back to the same fuel moistures we had at this time last year, and last year was one of the wettest years on record,” he said.
“Fuel moisture” is the amount of moisture contained within anything that can carry a fire, such as branches, trees, grasses, and shrubs. The higher the fuel moisture, the more resistant an object is to burning.
Prior to August, fuel moistures in the Eastern Sierra were at near-record low levels.
Beginning in early August, a series of monsoon-driven precipitation events swept into the Central Sierra, pushing in from the Gulf of Mexico. High temperatures created the right conditions for mountain thunderstorms. These storms tapped into a persistent and deep pool of moisture residing over Arizona and Nevada.
The end result was the Eastern Sierra received rain, and a lot of it, even as areas north and south of the region remained dry.
Although Reno-based National Weather Service meteorologist Scott McGuire said the final rain totals for August won’t be tallied until next week, he noted that just one storm—and that just last week—dumped about an inch of rain over the Mammoth area.
The end result is the region is now considered to be at a “normal” risk for fire, versus the “high” risk it was out three weeks ago, Iler said.
Shorter days, cooler nights, and less lightning characterize September compared to August, and those factors will help reduce fire danger, too, he said.
And, he said, there is another factor contributing to the reduced fire danger.
“The number of visitors in the area has dropped, and will drop even more after Labor Day, reducing the risk of human-caused fires,” he said.
Mammoth Lakes Police Chief Brent Harper strongly cautioned residents and visitors to stay alert and very careful.
“If these hot, dry winds continue, we could easily be back where we started,” he said.
In the short term, the Eastern Sierra is in for unsettled weather in the next few days, as more monsoon moisture heads into the area, possibly complicated by a now-dying hurricane, Ileana, which is projected to come onshore to Northern California early next week.
The monsoon moisture south of us, the increasingly warm temperatures over the next few days, and Ileana, will add additional chances for thunder and lightning storms and cloudy weather at least into mid next week, according to Mammoth’s amateur weather forecaster, Howard Sheckter.
Beyond that, looking toward the coming winter, McGuire said it is still too soon to predict the long-range forecast for the winter, but forecasters are looking for a “weak to moderate El Niño” pattern to set up in the Pacific Ocean.
Although the presence of the El Niño pattern is associated with some of the Eastern Sierra’s biggest winters, it is also associated with drier than normal winters, making it hard to predict the impact the phenomenon might have this winter.
Making things more complicated, the Eastern and Central Sierra lie “smack dab in the middle” of the cutoff latitude that divides the Climate Prediction Center’s forecasts for Northern and Southern California, McGuire said.