FLOOD10807 ‎(2)‎

• County: Statewide
• Community: Northeast Colorado
• Title: Notheast Colorado Emergency Managers' Association Hazard Mitigation Plan
• Date: 10/1/2003
• Prepared For: Cheyenne, Elbert, Kit Carson, Lincoln, Logan, Morgan, Phillips, Sedgwick, Washin
• Prepared By: Amec
• Floodplain - Doc Type: Flood Mitigation/Flood Warning/Watershed Restoration

· Heavy snow: Depending on the region of the USA, this generally means that four or more
inches of snow has accumulated in 12 hours, or six or more inches of snow in 24 hours.

· Ice Storm: A damaging accumulation of ice expected during a freezing rain situation.
Significant accumulations of ice are defined as one-quarter inch or greater. This can cause
trees and power lines to fall down causing the loss of power and communication.

Snow & Ice Storm Occurrences per County: 1950-2003
Cheyenne 16
Elbert 9
Kit Carson 20
Lincoln 6
Logan 11
Morgan 11
Phillips 0
Sedgwick 9
Washington 10
Weld 27
Yuma 15
11 County Total 134

Source: National Climatic Data Center

There are no official recurrence intervals calculated for snow and ice storms. Within the planning
area there have been 134 such storms between 1950 and 2003, a 53-year period. This equates to
an average of 2.5 severe winter storms per year. Severe winter storms are not only likely in
northeastern Colorado, they are expected each winter.

Drought
Drought has many definitions, even within the State of Colorado. They include:

· A prolonged period without adequate precipitation (Hazards in Colorado),

· A natural yet unpredictable occurrence in Colorado; An extended period of dry weather,
especially one injurious to crops (Colorado Drought Mitigation & Response Plan),

· A period of insufficient snowpack and reservoir storage to provide adequate water to urban
and rural areas (Colorado Climate Center at CSU, from 2003 Drought Impact and Mitigation
Report), and

· Meteorologic: based on degree of dryness; actual precipitation is less than expected average
or normal amount. Hydrologic: based on precipitation shortfall effects on streamflows and
reservoir, lake and groundwater levels. Socioeconomic: occurs when the demand for water is
greater than the supply due to a weather-related supply shortfall (FEMA, in Colorado's
Hazard Mitigation Plan)

The 11 county planning area has experienced 6 multi-year droughts since 1893, with the most
pronounced being in the 1930's and 1950's. The following chart is from the Colorado Drought
Mitigation & Response Plan.

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