Fiery hot summer expected
The Lake Tahoe Basin can expect fire conditions to be like last year – maybe even worse – as meteorologists predict drought conditions through summer.
Temperatures soared to record highs in March and April, causing a premature meltdown of snow into Lake Tahoe. But the lake is still well below what its natural rim should be – 6,223 feet above sea level, said Gary Barbato, hydrologist for the National Weather Service.
Water officials say in a normal year the lake level should be about 3.7 feet above the natural rim. To gauge how dry it is, Lake Tahoe is expected to be only 1.35 feet above its natural rim.
“The snowpack is pretty much done. If you look at the levels, on the rivers it is pretty dismal,” Barbato said. “We’re even behind where we’ve been the last couple of years.”
With warm temperatures, low humidity and drought, U.S. Forest Service officials say the mixture is contributing to another tinderbox summer.
To prepare for the annual fire season, Forest Service fire managers are preparing for the season, including training on-call wildland firefighters and offering refresher training for seasoned forest staff.
Drying out quickly
The Lake Tahoe Basin and much of the Sierra Nevada have just ended another below-average year for winter snowpack. In fact, what started out with promising precipitation amounts at the beginning of the year, fizzled to what it is today, about 77 percent of a normal year, Barbato said.
“We had a really dry March and April and now into May. In summer, we don’t have a lot of precipitation so we are looking to fall and winter before we can get any sizable amount,” he said.
Although a light spring snowfall occurred early this month, most of the moisture was quickly evaporated. With dry, warm weather returning, the forested lands of the basin will become highly sensitive to fire earlier than average, said Rex Norman, spokesman for the Lake Tahoe Basin Unit of the Forest Service.
Last year, fire restrictions were not imposed. If early drying continues, fire restrictions by summer are more likely, Norman said. Fire weather monitoring allows forest managers to evaluate the rate at which fuels that feed fires either retain or lose moisture. The drier the fuels, the easier it is for those fuels to burn. Currently, even heavier fuels that would normally retain more moisture longer are quickly drying out.
Southern California and the West Slope of the Sierra Nevada also are facing early dry conditions.
“Here in the Lake Tahoe Basin, we are moving into fuel moistures that would normally be seen later in summer. The Forest Service and fire protection district partners have a very good record of catching fires small, before many are even noticed by the public, and there are typically many such fires every fire season,” Norman said.
Fire in the basin more common than perceived
Many Tahoe residents may be unaware of how frequently fires have happened in the history of the basin. Prior to settlement, fires sparked mostly by lightning charred between 8,000 and 10,000 acres every year.
To counter the threat of wildfire to communities and resources, the Forest Service has treated more than 32,000 acres, primarily near vulnerable communities. Although there has been significant progress, more needs to be done. But fire managers warn Sierra and Tahoe residents not to assume that community defense treatments can “fireproof” communities.
Lake Tahoe Basin 30-year wildfire statistics:
n Wildfires, 1973-2003: 2,220
n Acres burned 1973-2003: 2,245
Principal causes over 30 years:
n Campfires: 22 percent or 495 fires or about 16.5 fires per year
n Lightning: 21 percent or 456 fires or about 15.2 fires per year
n Smoking: 17 percent or 368 fires or about 12.2 fires per year
The remaining percentages were all from varieties of human causes – both intentional and unintentional wildfires have occurred in every month of the year, with the majority in the period between June and September. Of the 2,220 wildfires in the last 30 years: there were 303 in June, 540 in July, 662 in August and 351 in September.
Lightning from passing summer thunderstorms on average sparks more than 15 fires each season, the second most common source of wildfire ignition, with 456 wildfires over 30 years. That is nearly as many natural as human-caused fires, Norman added.