Colorado Daily Status Report April 16


View or download the full Colorado Daily Status Report for April 16, 2014.

Flooding and Flash Flooding: Colorado Severe Weather Awareness Week

As we saw last September flooding can be a major problem in Colorado.

The flash flooding in September damaged a number of streams and mitigation is ongoing to remove debris and shore up heavily damaged areas along the streams in and near the foothills from Larimer County to El Paso County. The snowpack in the South Platte Basin is above normal so there is concern when the melt occurs that streams may not be able to handle a fast melt. The rate at which runoff occurs is dependent on a number of factors including the depth of the snow, how fast hot temperatures develop and whether thunderstorms drop heavy rain on the snowpack with runoff combining with falling rain. In 2011 we had a similar high snowpack with minimal flood issues as the warm days and cool nights moderated the rate of the snow melt. The peak snowmelt season is usually extends from late May through early June.

In September over eight inches of rain fell over a large area of the foothills from northern Jefferson to northern Larimer counties. All this rain filled area creeks and rivers causing considerable flash flooding. Runoff from area streams combined to cause major flooding along the South Platte River.

Flash flooding refers to dangerous sudden rise in water along a creek, river or over a normally dry land area. Flash floods result from heavy rainfall, sudden breaks in river ice jams and dam or levee failures. Flash floods can occur within a few minutes or hours and can move at surprisingly high speeds, striking with little warning. Flash floods are quite destructive because of the force of the moving water and the debris that accumulates in flood waters such as trees and boulders which can destroy roadways, bridges and buildings.

Other complications in Colorado are recent fires which raise the flood threat when locally heavy rain falls on recently burn scars. Residents in and near burned areas near Mancos, Debeque or in the Front Range Foothills from Larimer to El Paso Counties should plan ahead on response actions for flooding.

The National Weather Service will discuss flood and flash flood potential in daily hazardous weather outlooks and in the weather story on National Weather Service websites. On days with a high threat for flooding you may hear:

  • A flash flood or flood watch which means that flash flooding or flooding is possible within the watch area.
  • A flood warning which means that flooding is imminent or has been reported along a river.
  • A flash flood warning which means that flash flooding has been reported or is imminent. When a flash flood warning is issued for your area act quickly. If advised to evacuate do so immediately. Go to higher ground or climb to safety before access is cut off by flood waters.
  • An urban flood advisory will be issued for impact flooding that is not in itself life threatening. In an urban area if you were commuting during rush hour during a flood advisory you could expect some intersections to be underwater and a much longer commute. A small stream flood advisory might be issued when flow is bankful with minor lowland flooding along the stream.

Nearly half of all flash flood fatalities are vehicle related. Do not enter a flooded roadway, instead turn around, do not drown. In rapidly rising waters backing up away from water may be safer. One to two feet of water will carry away most vehicles and you also cannot tell if the road is damaged beneath moving water.

Colorado Severe Weather Awareness Week continues through this Saturday.




Spring Run Off Presentations

Presentations available from the Spring Run Off Forum hosted by the Colorado Division of Homeland Security and Emergency Management on March 19 in Estes Park.

View or download the five presentations.


Colorado Daily Status Report April 15

Colorado Division of Homeland Security and Emergency Management - DHSEM
Colorado Daily Status Report
*****April 15, 2014*****
Information in this report was gathered before 11:00 A.M.
NSTR = Nothing Significant to Report

Alerts/Warnings            
National Wildfire Preparedness Level - Level 1 – Updated 4/11/14 NIFC Sit Report
Rocky Mountain Preparedness Level - Level 1 – Updated 4/11/14 NIFC Sit Report

SEOC and Other EOC Activations
Duty Officer: (303) 472-4046
Emergency Operations Center (SEOC): Day to Day

View or download the full Colorado Daily Status Report for April 15, 2014

Tornadoes and Tornado Safety: Colorado Severe Weather Awareness Week

This is Colorado Severe Weather Awareness Week, a time when the National Weather Service reminds you of the hazards associated with thunderstorms. The topic for today is tornadoes and tornado safety.

The threat of tornadoes in Colorado increases rapidly in May and continues through August. Ninety percent of Colorado tornadoes occur during this four month period, but tornadoes have been reported as early as February and as late as October.

Tornadoes have been reported in just about all areas of the state, but historically 95 percent of Colorado tornadoes occur along and east of Interstate 25 where heat and moisture in the lower atmosphere are often more abundant. Tornadoes can occur at every hour of the day, but most occur between 1 p.m. and 8 p.m.

Across the country about 90 percent of tornadoes are considered weak with winds less than 110 MPH. Winds of this magnitude will damage a wood frame construction home but may completely destroy a mobile home or outbuilding. They typically have a life span under 10 minutes and result in less than five percent of tornado fatalities.

About 10 percent of tornadoes are considered strong with winds up to 165 MPH. Winds of this magnitude will cause considerable damage to most buildings. These tornadoes may last 20 minutes or longer and are responsible for nearly 30 percent of tornado deaths.

Violent tornadoes account for only one percent of all tornadoes, but they result in nearly 70 percent of all tornado fatalities because they destroy much of what is in their path. Violent tornadoes can last over an hour and travel over 50 miles before dissipating. The best chance of surviving a violent tornado is to be inside a safe room or underground shelter.

An easy phrase to remember for tornado safety is to get in, get down and cover up. Get inside a sturdy building, get down to the lowest floor or most interior room in that building and cover your head.

The best option for tornado safety is to be inside a well-built structure within a basement, safe room or underground storm shelter. If none of these options are available move to a hallway or a small interior room on the lowest floor such as a closet or bathroom. Cover yourself with blankets or get under a sturdy piece of furniture because the greatest risk of injury from tornadoes is from flying debris.

Abandon modular homes and mobile homes as they offer little protection from tornadoes. If a tornado approaches leave these locations and seek safety in a nearby building or storm shelter.

If you are driving in open country and see a tornado simply drive away from the tornado path if time permits. Do not take shelter beneath a highway overpass. If you are in an automobile and a tornado is fast approaching with little time for action either pull over and remain buckled in your vehicle while crouching down or abandon your vehicle and lie in a ditch or culvert away from your vehicle and protect your head.

If you are caught outside and cannot find a safe shelter crawl into a culvert or lie down in a narrow ditch and cover your head. But remember that these are poor, last-minute options because the worst place to be when a tornado threatens is outside in the midst of flying debris.

You can get the latest weather forecasts and severe weather watches and warnings from a local NOAA weather radio all hazards station and on the internet at weather.gov.

This guest blog written by David Floyd, Warning Coordination Meteorologist, NWS