Wet, cool weather keeps fire bans at bay
National forest campers across Arizona on Memorial Day Weekend are not likely to face any fire-use restrictions, thanks to unseasonably wet and cool weather in May.
It's already been three times wetter than an average May for Prescott, and the average high temperature so far in May has been only 68 degrees here, which is 7.5 degrees lower than the 117-year average.
"I think we have to go back quite a ways to see a May like this," said Prescott National Forest Deputy Fire Staff Officer Jeff Andrews, who has worked on this forest in various capacities for 25 years.
Over the past decade, the Prescott Forest lacked fire restrictions only in 2005 and 2011 during Memorial Day Weekend. In 2011, forest officials started restrictions on May 11 but then lifted them May 20 and didn't bring them back until June 8 because of a good storm.
The potential for large fires, called the Energy Release Component (ERC), hit at least a 20-year low on Saturday in the Prescott region of the forest. The current records system goes back to 1995. ERC components include moisture levels in dead and live vegetation.
So far this year the weather stations across the Prescott National Forest have recorded from 115 percent to 164 percent of average precipitation, Andrews said.
Unusually strong low-pressure systems have been fueled by warm waters off the West Coast, said Dave Vonderheide of the National Weather Service office in Flagstaff. Then they pull in cold Arctic air.
The best storm pulse of the month hit Friday and Saturday, producing 1.19 inches of rain at the Weather Service's official Sundog measuring site on the northeast side of Prescott. So far this month Sundog has recorded 1.47 inches of rain compared to the average of 0.47 inches. Snow fell on Spruce Mountain south of Prescott Friday, and the high temperature was only 49 degrees on Saturday.
It was a far cry from May 15-16, 2002, when the Indian Fire burned into the south side of Prescott during the driest year on record for the city. And last year, Prescott Forest fire restrictions began on April 18 and the Slide Fire ignited in Oak Creek Canyon north of Sedona on May 20.
Fire activity on the Prescott Forest has been slow this year, with only 12 wildfires burning a total of 12 acres.
The region could see more rain this weekend.
The weather gives people more time to prepare for the inevitable by clearing out brush and other continuous fuels for fire. While the fire season is likely to be shorter than normal, the region will have a fire season, Andrews said. All the moisture has fueled the growth of grasses that eventually will dry out, for example.
"At the end of the day, it is Arizona and it is going to get hot," Andrews said. "We have a fire season every year in Arizona.
"We don't want folks to let their guard down."
Federal fire forecasters are predicting above-normal wildfire danger for Yavapai County sometime between June and mid-July. The region remains in the grips of a long-term drought that has caused cumulative impacts.
Since 1970, the Prescott National Forest has experienced an average of 90 wildfires annually, with fires burning a total of 53 days a year. People caused 40 percent of them.
During some previous years with wet, cool springs, the subsequent monsoons arrived later than usual and were drier than average, observed Barry Wallace, Prescott Dispatch Center assistant manager who helps track fire weather on the forest.
"That's going to be the big question mark - the onset of the monsoon," he said. Vonderheide agreed. The region has to heat up and dry out to pull in monsoon moisture.
May's weather can't necessarily be attributed to El Nino because it's been so weak, Vonderheide said. But by the time fall arrives, the El Nino weather pattern should be settled in and it tends to bring wetter-than-average fall and winter seasons, Vonderheide noted.
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