California wildfires in the midst of winter

Mangled Jet Stream Sparks Drought, Winter Wildfires in Southern California — Colby Fire Explodes to Nearly 2000 Acres in One Day

(The Colby Fire at center mass. Image source: NASA)

Robertscribbler,

16 January, 2014

Major wildfires in winter? It may sound odd, but that’s what’s happening in a California suffering under a climate-change spurred drought that is currently its 9th worst on record.

Yesterday, beneath a dry dome of high pressure and spurred by Santa Ana winds, the Colby fire sparked in a populated suburb of Los Angeles amid a deepening California drought. Today, the fires exploded into a nearly 2,000 acre monstrosity. The blaze, fueled by 30 to 50 mph winds was proving difficult to contain as over 500 firefighters rushed to the scene in an effort to keep it from leaping down into nearby population centers. Mandatory evacuations were in place for hundreds of residents as the fire aggressively advanced toward homes and places of work.

(Colby Fire threatens local businesses. Image credit: Julie Palagyi)

Red flag warnings are now in place for many LA counties, which are expected to experience continued strong winds, above average temperatures, and single-digit humidity over the next 24 hours. Such conditions are conducive for the further spread of the Colby fire as well as for the sparking of additional blazes throughout the LA region.

Abnormally Warm, Abnormally Dry

Wildfires are rare in California this time of year. During winter, the region typically experiences wetter, rainier  and cooler conditions as storms flow in off the Pacific Ocean. But this year, a powerful blocking pattern has forced warmer, drier air over the region. It is the other side of the same blocking pattern that is flooding the Arctic with above average temperatures while disrupting the polar vortex and resulting in episodes of extreme weather over the eastern and central US.

(Jet Stream Pattern for Thursday and Friday. Image source: University of Washington.)

Note the very high amplitude ridge pushing up from California all the way into central Alaska and the corresponding trough digging down into the eastern US and pushing all the way to the Gulf of Mexico. This image is just a snap shot of the same blocking pattern that has persisted since late March of last year, resulting in wet, stormy conditions for the Eastern US and dry, hot, drought and fire conditions for the western US.

Blocking patterns of this kind have occurred in the past. But it is extraordinarily rare for such events to persist for ten months running. It is also the kind of event that climate experts such as Dr. Jennifer Francis warn is currently caused by a massive loss of sea ice cover in the Arctic and will become more common as sea ice continues its warming-induced retreat resulting in further Jet Stream weakening, meandering and retrenchment.

Weather Pattern Part of Trend Produced by Human-Caused Climate Change

This fixed weather pattern led to a rainfall deficit in California for December that, according to Dr. Jeff Masters at Weather Underground, was 4.67 inches below the seasonal average. This makes December of 2013 the 9th worst drought month on record for California. It is also worth noting that of the top ten worst drought months to occur since 1880 in California, five have now occurred since 1991 — a climate record that shows an increasing number of dry and record dry periods. Such increasingly extreme drying was predicted by numerous climate models for the US southwest as human warming continued to intensify and advance into the 21rst century.

Though such changes were anticipated by scientists, if not by politicians, business leaders, or the media, it was not clear that a strong fire hazard would emerge in even winter months. But this year has seen numerous intense west coast fires during winter time. Such new conditions are quite anomalous. And should the blocking pattern continue to persist, expect extreme heat, drought and fires to ramp up through spring and summer.

Links:

Plumes of Smoke Waft Through Colby Skies as Wildfire Rages

Historic Drought Intensifies in California

University of Washington

NASA

Extreme Red Flag Fire Warnings Across Southern California, As Drought And Wind Fuel Fire

A wildfire burns in the hills just north of the San Gabriel Valley community of Glendora, Calif., on Thursday, Jan 16, 2014. Southern California authorities have ordered the evacuation of homes at the edge of a fast-moving wildfire burning in the dangerously dry foothills of the San Gabriel Mountains

Think Progress,

16 January, 2014

On Wednesday, the National Weather Service issued a red flag fire warning for Kern County, north of Los Angeles, for the first time ever in January. Low humidity, strong winds and a lack of rain or snowfall has made the mountainous area especially susceptible the early onset of fire season.

Dry and windy conditions across the region have led to critical fire warnings in counties including Santa Barbara, Los Angeles and south toward the Mexico border, as well as some areas near the San Francisco Bay.

“Following the driest year on record, 2014 is kicking off as what may be the driest January on record in many locations in California,” weather.com senior meteorologist Jon Erdman said.

Los Angeles, which averages 14.74 inches of rain, ended 2013 with 3.4 inches. According to the Los Angeles Times, earlier this week a meteorologist warned that fire danger in many parts of Los Angeles and Ventura counties is “about as high as it can be.”

As of this morning a brush fire broke out near the edge of the Los Angeles National Forest. The 125-acre fire has prompted the response of at least 60 firefighters and caused mandatory evacuations.

“We’re fighting this fire extremely aggressively both on the ground and in the air,” Los Angeles County Fire inspector Scott Miller told local news.

On Tuesday a small but high-impact fire blazed through the hills near Pacific Coast Highway along Los Angeles’ Pacific Palisades, causing lanes to close for nearly six hours.

The Santa Ana winds contribute significantly to the fire hazard.

“Spawned by surface high pressure over the interior of the West, the Santa Anas form as the cold air flows toward Southern California, then speeds up and warms as it descends in a rush toward the coast,” reported the Weather Channel on Wednesday. “Some of the most extreme gusts reported by the National Weather Service topped 70 mph.”

Temperatures across the area have approached record highs all week and no rain is forecast in the near future. On Monday the high temperature at LAX was 83 degrees, matching the record for that date.

The Governor of California, Jerry Brown, is expected to announce that the state of California is officially in the midst of a drought in the next few days.

“It’s really serious,” Brown said on Monday. “In many ways it’s a mega-drought; it’s been going on for a number of years.”

According to a report released last August by the California Department of Environmental Protection, the state is already experiencing the impacts of climate change. As ClimateProgress reported, the study found “widespread evidence of the toll climate change is taking across the across the state, including more frequent and intense wildfires, rising sea levels, shrinking glaciers, warmer lakes and oceans, and hotter temperatures.”

Earlier this month surveyors found the Sierra Nevada mountain’s snowpack to be just one-fifth of normal for this time of year. Snowpack usually provides around one-third of California’s annual water use, but this year it could be more like one-twentieth. Even more — it is an indicator of the water challenges 2014 is likely to bring, as the longer-term impacts of the extreme dryness of 2013 take hold.