In the past, insurance companies have been unable or unwilling to provide flood insurance for the simple reason that one flood could bankrupt an insurance company; the risk of flood damage is too high and tends to happen all at once; it might not be covered by distributed premiums already collected. This is similar to the situation we Californians now see developing with earthquake insurance.

In order to make flood insurance available, Congress provided for the National Flood Insurance Program (NFIP) with the government acting pretty much as the insurer. But flood insurance was made available only on a community basis, and a community wishing to have flood insurance available had to join the NFIP and enforce the federal regulations by implementing them with local ordinances.

The NFIP was placed under the jurisdiction of the Federal Emergency Management Agency (FEMA) and its Flood Insurance Administration (FIA).

Palo Alto joined the NFIP in the late 1970s, and FEMA/FIA issued the first Palo Alto Flood Insurance Rate Maps (FIRM) in 1980. The FIRM are the official designator of the Flood Hazard Areas in the city. Of most interest are the Special Flood Hazard Areas (SFHA) since structures in these zones are subject to special insurance and construction requirements.

Flood Insurance Rate Maps (FIRM) and Panels
The FIRM for the City of Palo Alto is broken down into ten panels, numbered 0001 through 0010. However, because no flood study has been made of the Foothills section of the city, FIRM panels 0006 through 0010 have not been issued.

The City of Palo Alto also has a Community Number, 060348, which is unique. The complete designation for the FIRM would be the Community Number, and the Panel Number, and a letter indicating the revision level. Thus, a given parcel of land might be on FIRM 060348-0003D. At this time all Palo Alto FIRM panels are at either revision level D, indicating a revision date of 6 September 1989 or revision level E, indicating a revision date of 2 June 1999. (See also the information about Letters of Map Amendment and Revision - LOMA/LOMR).

Each of the issued panels shows a portion of the city at a scale of 1" = 500', showing the boundaries of the various flood zones. As might be expected, the scale is quite small and it is frequently difficult to determine the exact location of a flood zone boundary with respect to a given parcel of land, if that parcel happens to lie on or near the boundary.