Sometimes two perils act in the same event, but the policy covers only one of them. This is a concurrent cause situation, and California has specific answers for the two classic exam examples.

Fire following earthquake: Section 10088.5 keeps the insurer's duty under a fire policy to cover losses from a fire that is caused by or follows an earthquake. The fire damage is paid even though the earthquake set it off; the shaking damage stays uncovered unless earthquake coverage was bought.

Mudslide following wildfire: under Section 530 and the efficient proximate cause doctrine, the question is which cause was predominant, not which came last. Section 530.5 requires coverage when a loss results from a combination of perils including a mudslide and an insured peril is the efficient proximate cause. A wildfire that strips a hillside can be that cause months before the rain.

Agent tip: the Department of Insurance's 2025 notice applies this rule to wildfires and says insurers should investigate the cause diligently before denying such a claim.