A winter storm warning means you should be prepared for 6 inches of snow or 1/4th inch of ice. The National Weather Service displays it’s warnings on this web site. There are different types of snow storms in different areas of the country. A winter storm warning can mean any one of these types of storm is approaching. Usually, if there is a warning, the forecast will give details about what to expect and may even give a warning for the exact type of storm. Here some of the regional types of storm.
Blizzards are winter wind storms. The central plains of the US and steppes of Russia are good places to find blizzards. But even Iran has had blizzards in February 1972 and in January 2008. Blizzards have winds that are at least 35 mph, low temperatures, and falling or blowing snow. A severe blizzard has temperatures near or below 10 F, winds exceeding 45 mph, and visibility reduced by snow to near zero.
Nor’easters get their name because the storm travels to the northeast from the south and the winds come from the northeast. Such storms often are formed from two merging weaker storms, a cold front coming from the west and a low moving up the Atlantic coast. Nor’easters can happen at any time of the year, but the name is usually applied to winter storms. Nor’easters sometimes form eyes and usually appear similar to tropical storms which have traveled up to New England. However, the presence of fronts and the storm having a cold core keep the storm from being classified as tropical.
Lake Effect Snow
Lake effect snow occurs near the Great Lakes and the Great Salt Lake when cold air moves over warm water. Water vapor from the warm water forms clouds over the lake, causing snow showers and squalls as the clouds move downwind. So the southern and eastern shores of the Great Lakes, including Buffalo, NY, get this type of snow throughout the winter. Lake effect snow is generally lighter but more regular than a passing storm. When the moist air from the lakes crosses higher elevations, even more snow can fall. For example, the Tug Hill Plateau in New York State east of Lake Ontario can receive anywhere from 200 to 300 inches of snow in a winter. There is a similar effect on the west coast. Warm moist air from the Pacific Ocean is cooled when it blows up against the Cascade mountain range.
Freezing rain happens in storms when the temperature is near freezing, and warm air overruns cold air near the ground. Rain falls from the warmer air through colder air becoming sleet and hits the cold ground, forming ice. If the ice is more than 1/4th inch thick, the storm meats the criteria for being an ice storm. These conditions can also cause a winter thunderstorm, or thunder snow.