Winter Weather 101

Winter may be an enchanting season, but it's also a very dangerous time of the year.  A major winter storm can bring freezing rain, snow, high winds and below freezing temperatures.  And the ice from the storm can accumulate on and snap tree limbs and power lines leading to wide spread power outages.

Oklahomans know that a major winter storm can last for days, and its effect can be felt for weeks, even months.  In December '07 more than 640,000 Oklahomans were left without electricity following a powerful winter storm.  That storm also caused at least 27 deaths and an estimated $30 million in damage.  The December '07 storm was the second of the year.  In January of 2007, an ice storm lasting three days paralyzed portions of the state.  That storm caused trees, hundreds of power poles and power transmission lines to snap.  It was also blamed for at least 23 deaths, mostly from motor-vehicle accidents.

So what causes a winter storm to form?  Just like all severe weather a winter storm needs just the right combination of ingredients to develop.  Those ingredients are cold air, lift and moisture.  The cold air helps drop temperatures to below freezing.  Those cold temperatures form snow and ice when the temperature falls below 32^° F in the clouds and near the ground.  Lift is needed to form the clouds.  It raises moist air forming clouds that cause precipitation.  Moisture is also needed to form clouds and precipitation.  It is created when air blows across a body of water.

Most precipitation that forms in the winter starts as snow.  This is because the top layer of the storm is usually cold enough to create snowflakes.  A snowflake is a collection of ice crystals that cling together as they fall towards the ground. 

Winter storms can be accompanied by strong winds creating blizzard conditions, severe drifting and dangerous wind chill.  There are several forms of snow storms there are:

• Snow Flurries
• Snow Showers
• Snow Squalls
• Blowing Snow
• Blizzards

Snow flurries are light snow that falls for a short time.  There is usually no accumulation with snow flurries, just a light dusting of snow is left on the grounds.

Accumulations are possible during snow showers.  During snow showers snow falls at varying intensities over a brief period of time.

Snow squalls bring brief, intense snow showers with strong, gusty winds. Snow accumulations left behind from a squall can be significant.

Blowing snow is wind-driven snow that reduces visibility and causes the formation of snow drifts.  Blowing snow can be snow that is falling or loose snow on the ground that is picked up by strong winds.

Winds over 35 mph accompany blizzards.  The falling snow, strong winds and blowing snow mix together during a blizzard to reduce your visibility to a quarter of mile or less and it lasts for at least three hours.