Laserfiche WebLink
<br />Ramsey County | Multi-Jurisdiction Hazard Mitigation Plan 88 <br />• Extreme cold: The NWS doesn't have a set definition for extreme cold but instead calibrates the <br />point at which forecasters warn residents based on the region's climate. In Ramsey County, the <br />NWS issues “extreme cold” warnings when it feels like -25° F or colder across a wide area for <br />several hours. <br />• Ice storm: A storm that deposits at least .25” of ice on exposed surfaces. <br />Note that a single winter weather incident may include one or more of these, or other, winter <br />phenomena. <br />3.13.2 LOCATION <br />All communities within Ramsey County are vulnerable to winter weather. <br />3.13.3 EXTENT <br />Winter weather is typically forecasted three to seven days in advance by the NWS and can lead to the <br />issuance of a winter weather watch, warning, or advisory in a Hazardous Weather Outlook bulletin. <br />There are several types of these notices depending on conditions. Forecast certainty increases as the <br />time for storm onset decreases. <br />3.13.3.1 Winter Weather Watch <br />A watch is issued 24 to 72 hours in advance when there is a 50 to 80% chance of hazardous winter <br />weather meeting warning thresholds. It aims to give enough lead time for people to prepare and take <br />necessary actions. <br />Table 25. Winter Weather Watch Types <br />Watch Type Description <br />Winter Storm Watch Conditions are favorable for a winter storm event (heavy <br />sleet, heavy snow, ice storm, heavy snow and blowing snow <br />or a combination of events) to meet or exceed local winter <br />storm warning criteria in the next 24 to 72 hours. Criteria for <br />snow is 7 inches or more in 12 hours or less; or 9 inches or <br />more in 24 hours covering at least 50 percent of the zone or <br />encompassing most of the population. Use "mid-point" of <br />snowfall range to trigger a watch (i.e. 5 to 8 inches of snow = <br />watch). Criteria for ice is 1/2 inch or more over at least 50 <br />percent of the zone or encompassing most of the <br />population. This includes lake-effect snow. <br />Wind Chill Watch Conditions are favorable for wind chill temperatures to meet <br />or exceed local wind chill warning criteria in the next 24 to <br />72 hours. Wind chill temperatures may reach or exceed - <br />25°F. <br />Source: National Weather Service <br />3.13.3.2 Winter Weather Warning <br />These products are issued when hazardous winter weather is occurring, imminent, or highly likely (over <br />80% probability). A warning indicates conditions that threaten life or property.