With the prospect for a milder than average winter season, there is a different set of threats with the milder weather. Perhaps the most significant, and one we’ve already seen several times this early winter season, is freezing rain. Typically, most winter precipitation producing weather systems bring snow to the Red River Valley region, as the atmosphere is below freezing throughout the entire depth. In mild winters, warm air just several hundred - or thousands of feet above the surface - set the stage for freezing rain. The precipitation starts as snow falling from the clouds, then melts in this warm layer above the surface. When the melted snow - rain - falls to the ground, it freezes making for potentially dangerous conditions.
It only takes a few hundredths of an inch of rain to make roadways and walking surfaces very slick. Sometimes it becomes deadly, such as the weekend following Thanksgiving 2005. One to one and a half inches of rain fell over the southern half of the Red River Valley. The resulting Ice Storm caused millions of dollars in damage and left many thousands of people without electricity, in some instances for weeks.
The frequency of days with dense fog is also higher in winters when an El Nino occurs. Dense fog is defined when the visibility is reduced to less than one-quarter of a mile. When visibilities get this low, seeing other vehicles on the highways gets more difficult. Aside from reducing the visibility, dense fog can produce freezing drizzle, or deposit rime ice on roadways and walking surfaces. The result can be just as slippery as with freezing rain.
Another significant hazard is that ice may not become very thick on area lakes and rivers. This makes for a very hazardous situation, as ice-fishing may not be possible. Another favorite winter past time, snowmobiling on rivers and lakes may be impossible. Always check with the Department of Natural Resources or Game and Fisheries before venturing out on area lakes to be sure that the ice is thick enough to support you and any vehicles you intend to use.
So, while the warmer weather may be good news for the heating bill, it can also mean very good business for the automotive body shops.
Your NOAA’s National Weather Service wants to remind folks to keep a close eye on the weather, especially when traveling this Holiday Season. Be safe. Check the forecasts frequently before setting out. It’s also a good idea to listen to news and information while on the road. Carry a Weather Radio, as NOAA’s All Hazards Radio system is available in many areas of the country.
Keep these sites in mind before traveling.
Mark Ewens, Data Acquisition Program Manager