search

usgs / landslides-post-wildfire-debris-flow

A web application that displays estimates for the probability and volume of debris flows that may be produced by a storm in a recently burned area
Other
7 stars 6 forks source link

2018 webpage changes for Post-Fire Debris Flow website: Add FAQ #91

Open dstaley-usgs opened 6 years ago

dstaley-usgs commented 6 years ago

Add an FAQ page to the site. Here's the text for the page:

Frequently Asked Questions

What do the maps mean?

The maps depict the likelihood and potential volume of debris flows as they exit the mountain front in response to a design storm having a 15-minute peak rainfall intensity of 24 mm/h. The models are designed to assess the potential for debris flow in the locations where debris flows initiate (i.e., where they form and get larger).

Do the maps show where debris flows will travel?

No, the maps do not identify debris-flow runout paths, areas of inundation, or assess potential damage. Modeling debris-flow runout is very challenging, especially in populated areas, and developing predictive runout tools is an active area of USGS research.

It’s been a couple of months since the fire, will the maps be updated?

No, the maps only depict the hazard immediately after the fire. But the danger goes down over time as vegetation regrows and the soil recovers. In general, the debris-flow hazard remains elevated for 2-5 years after a wildfire. Precisely how long the danger lasts depends on many factors, such as how much it rains and how severely the slopes were burned. Quantifying the change in debris-flow hazard as the burned area recovers is an active area of USGS research.

What is the meaning 15-minute peak intensity of 24 mm/h?

A 15-minute rainfall intensity of 24 mm/h is equivalent to the accumulation of 6 mm of rain in 15 minutes. In English units, this is equivalent to approximately 1/4 of an inch of rain in 15 minutes.

Why use a 15-minute peak intensity of 24 mm/h design storm?

This design storm is used for three reasons: (1) Post-fire debris flows are most often triggered by high-intensity, short-duration bursts of rain. (2) A 24 mm/h rain burst is likely to happen in most areas of the western U.S. (i.e. a 1-5 year recurrence interval). (3) A 24 mm/h rain burst is known to trigger debris flows at USGS monitoring sites in burn areas. Are results for other storm scenarios available? Yes, other design storms are contained in the geospatial data available for download. These storms have peak 15-minute intensities ranging from 12 to 40 mm/h in 4 mm/h increments.

How do I get a post-fire debris flow hazard assessment?

See Assessment Requirements page.

I live near a recently burned area. Am I in danger?

Contact your local authorities to learn about emergency-response and evacuation plans for your area.

jwkean commented 6 years ago

I'm hoping we can get some progress on this soon, because we are now in full fire season and need these web page updates.

jmfee-usgs commented 6 years ago

Can you provide more information about the specific page were you want this information? @lisa-usgs may be able to add this in certain locations sooner than others.

https://landslides.usgs.gov/hazards/ https://landslides.usgs.gov/research/wildfire/whattodo.php https://landslides.usgs.gov/hazards/postfire_debrisflow/ etc...

lisa-usgs commented 6 years ago

This new webpage is in /research/wildfire/faq.php