On Wednesday and Thursday, high seasonal winds will tear through California, drying out vegetation and fanning wildfires. The conditions could easily spell a devastating, deadly conflagration. In preparation, early Wednesday morning the utility PG&E—whose equipment sparked last year’s Camp Fire, which killed 86 people and destroyed the town of Paradise—will begin preemptively shutting off power to a staggering 800,000 customers.

Those customers are not happy, and for good reason: Losing power is a hassle for anyone, but it’s potentially deadly for those who rely on electrical medical devices. Businesses lose business, food spoils in warming fridges, and critical infrastructure goes offline. But this is no shot in the dark—meteorologists can predict where and when those winds will grow dire, so PG&E can target their shutoffs. It’s a calculus that climate change is making increasingly familiar. But blaming the climate alone would be letting California off the hook. Its policies and building habits are also responsible for the darkness that must now descend on northern portions of the state.

加州野火问题,从对比的冲突增长。在每年的这个时候的气氛,压力在气团在大盆地积聚,东州。同时,低压区域需要在海岸附近的形状。因为空气倾向于从高转向低气压地区,风开始从向海岸东北加速。该压力梯度越大, the stronger the winds.

随着风动内华达山脉在加利福尼亚州东部,他们像流动的水在岩石流,压缩和气候变暖。穿越山谷切片,风收集更多的速度,在的干燥剂空气。 “如果你想象在你的头上海绵的氛围中,你不能拧干了,”丹尼尔·斯温,气候科学家在加州大学洛杉矶分校说。

At ground level, the warm air screaming through the mountains sucks away whatever moisture might be left in the vegetation—which is increasingly little as the climate warms in California and autumns grow increasingly dry. What’s left is a parched landscape that’s primed to burn, and winds of 60 or 70 miles per hour can speedily turn a spark into a fast-moving wildfire. Such was the case in last year’s Camp Fire: Winds picked up embers and blew them perhaps a mile ahead of the main conflagration, setting a multitude of small fires throughout the town of Paradise, overwhelming firefighters.

Because meteorologists know why and when and where these winds form, they can use models to give perhaps a week’s warning of a major wind event, like one coming up. Ground-level data, like topography, sharpens the forecast to show where winds might be fiercest. So PG&E is cutting off power in the particularly dangerous zones it has identified in Northern California, where high winds might rustle power lines and shower sparks onto the wind-parched vegetation below. Specifically, says PG&E spokesperson Ari Vanrenen, they’re looking for humidity levels below 20 percent and sustained winds above 20 mph or gusts over 45 mph.

If the conditions align, PG&E initiates what it calls public safety power shutoffs, and they’re tortured decisions. “It is sort of unprecedented for such a large utility doing this preemptively,” says Swain. “They are probably an unfortunately necessary stopgap fire-prevention measure right now, but they come with serious risks as well.”

A utility like PG&E is mandated to provide power, because doing so isn’t just a matter of modern conveniences—it can be a matter of life and death. That’s especially true in the Golden State's mountain towns that are most at risk of catastrophic wildfire, many of which are retirement communities. The elderly may rely more heavily on medical appliances and be more vulnerable to heatstroke without air conditioning. By preemptively cutting off power, you’re also potentially cutting off communication—if the power goes out and a wildfire starts, and TVs and internet routers don’t work, people could be at risk. Electric water pumps too would go offline, potentially hampering firefighting efforts.

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In preparation for the shutoffs, PG&E recommends stocking up on food and water and flashlights, but that might be difficult for people with fixed incomes and limited mobility. You’ve got to think of the little things, too, like opening your garage before a blackout in case a wildfire does come and you need to flee and your opener is kaput. If you’ve got a generator, great; but ironically enough, more generators humming along outdoors means more ways to spark the fires PG&E is trying to prevent.

The hard truth is that California is built to burn。几十年来,国家已冲出大火,而不是让其自然燃烧,造成燃料积累。而加州不禁在风漏斗谷守楼院正对着荒地,经常把自己从字面上火线狙击。

PG&E bears outsize responsibility for this mess;其糟糕的安全记录包括在2017年单独17个主要野火。在电气线路英里英里纵横交错的景观,提供用于点火充足的机会。一个解决办法可能是掩埋线路,但价格昂贵,往往在岩石区不可行。在一个理想的世界中,所有这些山区乡镇的将自己自足,太阳能供电的微电网运行, but that too is wildly expensive.

And really, fires will always have reasons to start—a firework here, an overheated car or cigarette ember there. In these times of climate change, drier brush means Californians must live with the constant anxiety that it’s not a matter of if the next Camp Fire will strike, but when and where.

“即使你阻止90%的野火点燃的,其余的大火可能是一样糟,甚至更糟的是,”加州大学洛杉矶分校指出的情郎。 “仍留给我们的字符和野火的强度正在改变的问题。即使我们看到它们的数量较少,我们还是会产生灾难性的火灾“。

Add catastrophic power outages to the list. All is not well out west.


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Matt Simon is a science journalist at WIRED, where he covers biology, robotics, cannabis, and the environment. He’s also the author of Plight of the Living Dead: What Real-Life Zombies Reveal About Our World—And Ourselves, and The Wasp That Brainwashed the Caterpillar, which won an Alex Award.