Dry brush in the Santa Cruz Mountains.
A firefighter battles one of the CZU Lightning Complex blazes in August.
(Kevin Painchaud / Lookout Santa Cruz)

Red flag warning: Fire risk turns dire in Santa Cruz County

A combination of strong winds and low relative humidity led to the National Weather Service issuing the red flag warning through Monday at 11 a.m.

A red flag warning — the official notice that fire conditions are at their most dire — has been issued for the Santa Cruz Mountains and other parts of Northern California through 11 a.m. Monday.

A combination of strong winds and low relative humidity resulted in the National Weather Service issuing the warning late Saturday. It’s the first such warning of its kind since December 2017.

In the Monterey Bay and San Francisco Bay areas, meteorologists are predicting:

  • Gusty northeast winds will arrive Sunday night, and then peak around sunrise Monday morning. Wind gusts will hit 45 to 60 mph in the hills and 30 to 45 mph into lower elevations.
  • Humidity values will stay in the “moderate” category — about 35% to 50% overnight before drying Monday afternoon to 30%.
  • Strong offshore winds will blow Sunday night through midday Monday. Winds will be strong enough to bring down trees, branches and cause power outages, the weather service says. Meanwhile, as strong winds blow, fuels — the brush and trees that burn in wildfires — are drier than they’ve ever been for this time of year.

So far, PG&E is not predicting any electricity shutoffs in Santa Cruz County as a result of fire risk. Consumers can check on potential future outages by clicking here.

Fires — and fire risk — have been a statewide problem this summer and fall. Southern California is already on fire: as of Friday the Bond fire in Orange County had burned 6,400 acres, forced evacuations of more than 20,000 people.

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In Northern California, Duane Deykema, a forecaster with the weather service’s Bay Area/Monterey Bay office, advised residents to “be careful. Any outdoor burning definitely is not recommended during this event. Anything that might create a spark.”

Red flag warnings are only issued when some combination of factors align: strong winds, low relative humidity, dry fuels, and/or the possibility of dry lightning strikes.

Dry conditions in the Santa Cruz mountains
Dried-out plants and brush in the Santa Cruz Mountains on Friday are contributing to a high risk of fire Sunday into Monday.
(Kevin Painchaud / Lookout Santa Cruz)

The strongest winds will be mostly across the northern end of the mountains, and the sustained winds are likely going to be 10 to 20 miles per hour. This wind scenario is conducive to fire, and another important factor is too: fuel.

Fuel in the Santa Cruz and Diablo mountains is as dry as it’s ever been since the forest service started keeping records. The area has been sunny, warm, and rain-free for most of the fall, with the Santa Cruz mountains currently at just 30% to 40% of its average annual precipitation.

While there was rain in Northern California, including in Santa Cruz, a couple of weeks ago, there have “a lot of very dry days, and the fuels” dried up again,“ Deykema said. If you get enough rain, “the fuels are sufficiently moist to tide you over until the next rain.” That didn’t happen this time because it’s been so dry.

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