A year ago, while on a tourist visit to Latvia, Sharon Bard was awoken at 4 am by a buzzing alert from her phone. It was an email from a friend who’d been checking on her home in Santa Rosa, California. Given the alarming news, the email's phrasing was rather gentle: A fire had broken out in the area, officials had ordered evacuations, and Bard’s country house at the end of a road might be affected. Then came the deluge.

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