With much of state, Marin is in a moderate drought

04/22/2020

Winter is over and the rainfall recorded since last October is low. California saw less than half the average amount of rain—including a record-setting, bone-dry February—and Marin was no exception, with 40 to 50 percent of normal levels reported countywide. The Inverness Public Utility District offered an illustration of these percentages: it documented 19 inches of rain from October through March, compared to the average of 33 inches. March offered a little reprieve after a month of clear skies, with 2.21 inches of rain. The rest of the spring could change this ranking, but, so far, those numbers mark the sixth driest year in Inverness in the past 90 years. According to the United States Drought Monitor, a weekly report issued by the National Oceanic and Atmospheric Administration, Marin is experiencing moderate drought conditions. This means that pasture growth is stunted, landscaping and gardens will need irrigation earlier, and stock ponds and creeks are lower than usual. Forty-three percent of the state falls under the moderate drought classification, and an additional quarter of the state is abnormally dry. Snowpack statewide is 63 percent of normal. This represents a change: last year in March, the drought monitor determined the vast majority of the state was free of drought for the first time in seven years. Anna Schneider, a meteorologist for NOAA in Monterey, noted that the drought monitor tracks precipitation and not stored water levels. “Our reservoirs are still in pretty good shape,” she said. Locally, that’s true: at the beginning of April, the Marin Municipal Water District reported 97 percent of average storage levels for the time of year. Still, vegetation feels immediate effects from an abnormally dry winter. “Our reservoirs aren’t at the moment in terrible shape, but the natural vegetation doesn’t know anything about that,” said Dr. Daniel Swain, a climate scientist at the University of California, Los Angeles. He pointed to the national predictions of fire threat for the state released this month. The forecast for Northern California published by the National Interagency Fire Center determines that wildfire activity is more likely higher than average through July, but that the March rains had improved fire-fighting ability, especially at lower elevations. “The wet unsettled weather impacting the region in late March is expected to wind down in early April, leading to a return to warm and dry weather,” the report states. “There [will be] warmer and drier than average conditions through July, although brief periods of cool wet weather are still expected into early June. New ignitions are expected to occur more frequently than usual [through July]. But, at lower elevations the new green grass crop will aid firefighters in quickly gaining control.” Dr. Swain said California historically has greatly varied rainfall year to year, but that effects on the landscape are predicted to intensify. His research suggests that the amount of rainfall that drops each year is not expected to change, but that the patterns of when and how it falls will alter; already, rain is falling in bigger, shorter bursts. This brings an increased risk of flooding and wildfire. “We expect an amplification of what we are already used to, an acceleration of this extreme seasonality we already have,” he said. “It’s wet in the winter, and dry in the summer, and there’s some level of transition in spring and autumn. We will see an increase in the sharpness of this seasonality, increasing flood risk during the core wet season months and increasing fire risk the rest of the time.”