Floods and Flood Warnings

…FLOODING CAN BE A MAJOR PROBLEM ACROSS COLORADO…

Today’s topic during this Flood Safety and Wildfire Awareness Week is flooding which develops in the time frame of longer than 6 hours to several days.

Notable floods across the Centennial State:

June of 1921 - A flood along the Arkansas River devastated the City of Pueblo. Scores of people drowned.
Memorial Day 1935 - Catastrophic flooding occurred on the Palmer Divide and the Colorado Springs area. Flooding caused millions of dollars of damage, and drowned at least 18 people.
June 1965 - Widespread flooding across eastern Colorado took several lives and caused over 500 million dollars of damage.
April and May of 1999 - A major flood occurred across southeast Colorado after heavy rain (up to 14 inches) fell in the area. There was major flooding from Colorado Springs to La Junta.
September 2013 - Historic rains and floods in September caused over 3 billion dollars of damage, and took 9 lives.
May 2015 - Multiple days of heavy rain and snow caused flooding across many areas of eastern Colorado.

Flood Causes

All floods are caused by there being too much water for a stream channel or riverbed to contain. In Colorado this can be caused by rapid snow melt, ice jams, a combination of snow melt and heavy rain, or just heavy rain.

National Weather Service and Flooding

Four different National Weather Service River Forecast Centers monitor the rivers in Colorado. Forecast Offices in Colorado closely collaborate with these River Forecast Centers to come to a consensus on the likelihood of flooding along rivers and large creeks.

The National Weather Service provides a number of products and services that discuss the possibility of flooding. These include:

Hydrologic Outlooks
Hazardous Weather Outlooks that are issued daily
Graphical Weather Stories on National Weather Service web sites
Hydrologic Statements that may be issued for high flows that are within the banks of a river or large creek

When weather conditions become more favorable for flooding the National Weather Service will issue more directed products about conditions on rivers and large creeks.

A Flood Watch will be issued on days when flooding is more likely on a river or large creek. A Flood Watch means flooding in the area is more likely than on a normal day, but that flooding is not currently expected.
A Flood Warning will be issued when flooding is forecast or occurring. A Flood Warning means flooding is expected or has been reported at designated river forecast points.
Flood Advisories may be issued for minor flooding on rivers and creeks.
Areal Flood Warnings may be issued for flooding on parts of rivers or large creeks not covered by designated river forecast points.

You Can Monitor Flooding

The National Weather Service created the Advanced Hydrologic Prediction Service monitoring system. With this system you can easily monitor potential flooding along rivers and large creeks in Colorado. The address for this system is below.

https://water.weather.gov/ahps

This monitoring system can be accessed on Colorado National Weather Service forecast office web sites by clicking Rivers and Lakes.

Each designated river forecast point in the area is shown on the web page. You can look at current and forecast conditions, flood categories, historic crests, and flood impacts for each site. Probabilities of exceeding certain water levels by week or over the long term are also available.

You Can Prepare Yourself

In general, there will be some time to prepare for flooding along rivers and large creeks. Emergency management in your area has plans in place to address flooding issues. Know these plans and how you should act when Flood Watches and Flood Warnings are in effect.

For more information on flood safety go to:

https://www.weather.gov/safety/flood

The topic for tomorrow is flash flooding. These floods occur very quickly, can be very intense, and are frequently life-threatening.