Blizzards: Snow and Ice

Storm - Any disturbed state of an environment or astronomical body's atmosphere especially affecting its surface, and strongly implying severe weather.  It may be marked by significant disruptions to normal conditions such as strong wind, hail, thunder and lightning (a thunderstorm), heavy precipitation (snowstorm, rainstorm), heavy freezing rain (ice storm), strong winds (tropical cyclone, windstorm), or wind transporting some substance through the atmosphere as in a dust storm, blizzard, sandstorm, etc.

Blizzard - A snowstorm becomes a blizzard when wind speeds reach more than 56km/hr.  Temperatures in these conditions can drop to -12°C and visibility is poor, typically lasting three hours or more.

Ice storm - (Not a blizzard)  These occurs when a rain-bearing warm front arrives in an area of cold dense air, and the rain freezes as soon as it lands.

Winter storm - An event in which the varieties of precipitation are formed that only occur at lowtemperatures, such as snow or sleet, or a rainstorm where ground temperatures are low enough to allowice to form (i.e. freezing rain).

Jet stream - A narrow variable band of very strong predominantly westerly air currents encircling the globe several miles above the earth.  There are typically two or three jet streams in each of the northern and southern hemispheres.

A low-pressure area (depression) - A region where the atmospheric pressure islower than that of surrounding locations.  Low-pressure systems form under areas of wind divergence which occur in the upper levels of the troposphere.

Snowdrift - a deposit of snow sculpted by wind into a mound during a snowstorm. 

Whiteout - A condition of diffuse light when no shadows are cast, due to a continuous white cloud layer appearing to merge with the white snow surface.  No surface irregularities of the snow are visible, but a dark object may be clearly seen.  There is no visible horizon.

Ground blizzard - A weather condition where loose snow or ice on the ground is lifted and blown by strong winds.

Nor'easter - a macro-scale storm along the upper East Coast of the United States and Atlantic Canada; it gets its name from the direction the wind is coming in from the storm.