Urban Drainage and Flood Control District Urban Drainage and Flood Control District Early flash flood prediction, detection, notification & warning for the greater Denver/Boulder metropolitan area since 1979 NOTE: This slide contains Internet hotlink

Buffalo Creek lives lost Big Thompson dead or lost Cheyenne deaths Rapid City dead

Basic Elements of Warning Plan n Early detection and evaluation of the threat n Dissemination of the warning n Response by those at risk to the warning All three elements must function properly or the plan will fail.

Early Detection & Evaluation For flash flood threats this process needs to begin before it rains for the warning process to be truly effective. Flood Threat Recognition

Weather Station in Aurora Rain Gage Maintenance ALERT Stream Gage housed with USGS gaging station on South Platte River in Denver Rain & Stream Gage at Ralston Reservoir in Jefferson County ALERT Gaging Stations local vesting in the process

Westerly & Toll Gate Ralston Boulder & S. Boulder Lena Bear Goldsmith/Harvard Basin-specific flood warning plans

Denver/Boulder Area ALERT System automated real-time gage network Flood Detection Networks 1978 Boulder Creek 1980 South Boulder Creek 1982 Lena Gulch 1986 Ralston Creek 1987 Westerly Creek 1988 Toll Gate Creek 1989 Goldsmith/Harvard Gulch 1989 Bear Creek 1997 Douglas County ALERT Stations & Sensors 124 Rain Gages 69 Stream Gages 15 Weather Stations 6 Repeaters 8 Base Stations This extensive network includes more than 260 sensors and 145 stations.

ALERT Users in Colorado

Data Interpretation Aided by Graphical Displays

STORM Watch (Windows-based software by DIAD Inc.)

NOTE: This slide contains Internet hotlink

Meteorological Support n Supplements NWS watches & warnings n Maintains direct contact with local government emergency preparedness and response agencies n Tailors communications to specific jurisdictional concerns n Supports comprehensive multi- jurisdictional basin flood warning plans

Meteorologists monitor weather radar and other real-time data sources to keep local officials informed concerning threatening conditions.

Standard F2P2 Messages (relayed by voice and fax to dispatchers) MESSAGE 1 (Internal Alert) This is an advisory message which is meant to inform key people that weather conditions are such that flood producing storms could develop later in the day. It will be issued by HMS after consultations with NWS. If HMS feels this weather advisory requires priority handling by the communications dispatcher, the message will be preceded with the statement: "THIS IS A RED FLOOD ALERT MESSAGE." MESSAGE 2 (Flash Flood Watch) This message indicates that a Flash Flood Watch has been issued by NWS and/or HMS feels the risk is high that a life-threatening flood may occur later in the day. HMS will add any additional information which is available. If HMS feels this watch requires priority handling by the communications dispatcher, it will be identified as a RED FLOOD ALERT message.

MESSAGE 3 (Flash Flood Warning) This message indicates that a Flash Flood Warning has been issued by NWS and/or HMS feels that a life-threatening flood is imminent. Again, HMS will add any additional information which is available. This warning message requires priority handling by the communications dispatcher (i.e. an automatic RED FLOOD ALERT). MESSAGE UPDATE This message will be used by HMS to update any of the previous messages, particularly in the event of a disagreement between HMS and NWS. For example, this message can be used to narrow a watch or warning area as more information becomes available or to provide more site specific data and direction during an event. If HMS feels this update requires priority handling by the communications dispatcher, it will be identified as a RED FLOOD ALERT message. MESSAGE 4 (All Clear) This message cancels the flood potential status. This message is issued by HMS after consultation with NWS and other entities involved with direct HMS communications.

Standard F2P2 Message Forms n All F2P2 “Messages” are communicated by phone to dispatchers. n Standard forms are faxed to dispatchers prior to phone call to minimize the potential for misinterpretation. n Copies of forms are included with all District-support basin flood warning plans.

Other F2P2 Products via Broadcast Fax & Web n Daily Heavy Precipitation Outlook (HPO) issued by 11:00 a.m. HPO n Internal Message Status Report (IMS) replaces HPO when a “Message” is in effect. IMS n Probabilistic Quantitative Precipitation Forecast (QPF) provides more detailed basin-specific information. QPF n Storm Track (ST) provides hour lead describing movement, size, QPF and expected path. ST NOTE: This slide contains Internet hotlinks

Dissemination Example for Jefferson County, Colorado Weather/flood messages relayed by emergency communication centers. More than 30 known point contacts for Jeffco. Subsequent relays unknown. * Private Meteorological Service District Flash Flood Prediction Program

‘High Tech’ helps save lives, but it does not replace the need for the ‘High Touch’ observations and communications that people provide.

Used to predict flood potentials and storm tracks, and to identify meteorological triggers before if rains. Weather Station Mesonet

ALERT Weather Station a forecast tool & more u Precipitation u Wind Speed/Direction u Wind Gusts u Air Temperature u Relative Humidity u Dewpoint (calculated) u Fuel Moisture & Temperature (fire weather) u Key pre-storm flood forecasting parameters Hiwan Golf Course near Evergreen, CO

THE ALERT MESONET

How well does all this stuff really work? August 17, 2000

Rocky Mountain News n August 18, 2000 n August 19, 2000 n August 22, 2000 n Sept. 1, 2000

Building Relationships 38 Local Government Partners Private Meteorologists Media & Others