AZGS resources for post-wildfire flooding and debris flows in Arizona

AZGS geologists are working with our state and federal counterparts to assess the potential for post-fire flooding and debris flows.

The Arizona Division of Emergency Management (ADEM) put out this announcement about the meeting of tribal, federal and state agencies to discuss potential post-fire flooding threats in communities impacted by the Wallow, Horseshoe Two and Monument fires earlier this week.

Attendees discussed a number of issues, including the average monsoon rainfall in those area, the status of rain gauges and the utility of existing flood warning systems. Chief among them was the need for outreach to at-risk communities about the importance of being prepared and adequately insured.

Agencies in attendance included the San Carlos Apache Tribe; the Arizona departments of Environmental Quality, Game and Fish, and Water Resources; the State Forestry Division; the Arizona National Guard; the National Weather Service, the U.S. Geological Survey, the Department of Homeland Security; FEMA; the federal bureaus of Indian Affairs and Reclamation; and the U.S. Forest Service.

Data models created cooperatively by experts in such fields as hydrology, geology, forestry and civil engineering will be shared with at-risk communities. In turn, these communities will lead the planning for flood mitigation and response.

Most homeowners’ insurance policies do not cover flood damage, but most agents who sell homeowner’s insurance also sell federal flood insurance policies. Detailed information about the National Flood Insurance Program (NFIP) is available online at www.FloodSmart.gov or with a call to the NFIP referral center at (888) 379-9531. It takes 30 days for an NFIP policy to go into effect.

Although the flood risk of an area might increase, insurance premiums do not. Rates are based on flood maps that do not immediately change after a fire event. Home and property owners can learn their level of flood risk at www.FloodSmart.gov.

Visit the Arizona Emergency Information Network (AzEIN) website at www.AzEIN.gov for real-time emergency updates, preparedness and hazard information, and multimedia resources.

Some relevant AZGS hazards resources are posted online for free viewing and downloading:

OFR-90-6-Controls on the Origin and Recurrence of Debris Flows in the Huachuca Mountains, Southeastern Arizona, by E.E. Wohl and P.A. Pearthree, 1990, 48 p.

OFR-08-08- Delineating Post- Wildfire Debris Flow Hazards for Pre-Fire Mitigation, Pine and Strawberry, Arizona: A FEMA 5% Initiative Study, 2008, 20 p.

DM-DF-1 Geologic Mapping of Debris-flow Deposits in the Santa Catalina Mountains, Pima County, Arizona. 2008, A. Youberg and 4 others, report and 11 map sheets.

CR-11-A Movement of Channel-borne sediments in the 2010 Schultz fire burn area, 2011, by M. D. Carroll.

Fire and Sediment Deposition, 2004, P. Pearthree, Arizona Geology, V. 34, #3, Fall 2004

Wildfire, Rain and Floods: A Case Study of the June 2010 Schultz Wildfire, Flagstaff, Arizona, 2010, A. Youberg, K. Koestner and D. Neary, Arizona Geology, V. 40, #3, Winter 2010-11

Recent Debris Flows and Floods in Southern Arizona, 2006, P.A. Pearthree and A. Youberg, Arizona Geology, V. 36, #3, Fall 2006.