National Weather Service Warnings for Flash Floods and Debris Flows - - PowerPoint PPT Presentation

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Mar 22, 2024 523 likes •709 views

National Weather Service Warnings for Flash Floods and Debris Flows Alex Tardy - Meteorologist Weather.Gov Building a Weather-Ready Nation Warning Notification Flash Flood Watch potential for FEMA alert app heavy rain exceeding

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Building a Weather-Ready Nation

National Weather Service Warnings for Flash Floods and Debris Flows

Alex Tardy - Meteorologist Weather.Gov

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Building a Weather-Ready Nation

Warning Notification

Flash Flood Watch – potential for

heavy rain exceeding thresholds today or tonight

Flash Flood Warning – heavy rain

is occurring or imminent and flooding is expected along with possible debris flow for “defined area”

Threshold for rainfall (rate per hour)

would be met and burn scar would be mentioned in Flash Flood Warning if affected

W th /S Di

FEMA alert app

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Building a Weather-Ready Nation

Wireless emergency alerts

TV and radio EAS alerts

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Building a Weather-Ready Nation

Wireless Emergency Alert in polygon

NWS Warning polygon

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Building a Weather-Ready Nation Monitoring weather from the Emergency Operations Center and NWS

NWS San Diego

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Building a Weather-Ready Nation

Rain showers on Weather Radar Showers came in late Wednesday evening October 3 (Orange County)

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Building a Weather-Ready Nation

Rainfall from Showers

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Building a Weather-Ready Nation

https://www.wrh.noaa.gov/sgx/kml/holyfire.php

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Building a Weather-Ready Nation

Flash Floods and Debris Flows

National Weather Service

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Building a Weather-Ready Nation

Burn assessment

Cranston Fire Scar

USGS and USFS report

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Building a Weather-Ready Nation

Monsoon thunderstorm

Rainfall can be localized

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Building a Weather-Ready Nation

Radar estimated (no gauges)

Rainfall Distribution

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Building a Weather-Ready Nation

Basin level for each drainage

Flash Flood monitoring

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Building a Weather-Ready Nation

Force and depth of flash flood debris flow

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Building a Weather-Ready Nation

Atmospheric River

Jet Stream highest moisture in yellow and red

BIG storms

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Building a Weather-Ready Nation

Rainfall is widespread but localized heavy

Winter Storm

This type of “embedded rainfall” can cause high rain rates and debris flows

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Building a Weather-Ready Nation

Partnering with Caltrans

TADD program

http://www.nws.noaa.gov/os/water/tadd/ Weather.Gov