A flood claim goes to your NFIP or private flood carrier, not to your homeowners insurer — they are separate policies and a homeowners claim will be denied for flood water. Report it the day you find it. NFIP requires a signed Proof of Loss, normally within 60 days of the loss, and the documentation you gather in the first hours is what it is built from: video of every affected room before anything is moved, photographs of the high-water line, a list of damaged contents with what you paid, and receipts for emergency mitigation.
Idaho homeowners should verify their policy covers snowmelt-driven water intrusion and frozen pipe damage, as many standard HO-3 policies exclude gradual water seepage common during the March–May Snake River Valley spring thaw; pipe freeze coverage often requires proof of maintained interior heat. Mitigation is not optional — every policy requires you to stop further damage, so drying starts before the adjuster arrives, and you keep the invoices.