Frances Mann-Craik loves living amid the trees along Highway 35. But her quiet life in the mountains above Silicon Valley is about to get a lot more expensive.

Along with more than a dozen of her neighbors, Mann-Craik recently received a letter from Walnut Creek-based CSAA, a AAA insurer, informing her the company would not be renewing the fire coverage she’s had for nearly two decades.

In an Aug. 20 letter sent two months before her coverage expires, the company said it had changed requirements for home insurance policies and that "based on the new requirements, we are no longer able to continue providing insurance coverage for your property."

CSAA is not the only insurer dropping customers. Across the Bay Area, from the Berkeley hills to the Santa Cruz Mountains, insurance companies are declining to renew policies that include fire coverage -- sending families scrambling in the heart of fire season to lock down alternatives that tend to be more costly and less comprehensive.