BREAKING NEWS BLIZZARD According to the U S National Weather Service NWS a blizzard is a storm that lasts at least three hours and includes large amounts of falling or blowing snow Blizzard winds are faster than 35 miles 56 km per hour and visibility is less than 1 4 mile 0 4 km A severe blizzard is one with temperatures below 10 F 12 C winds above 45 miles 72 km per hour and visibility near zero THE BACKSTORY OF BLlZZARDS THE WORD BLIZZARD ORIGINALLY MEANT A LARGE AMOUNT OF GUNFIRE IN THE 1870S A NEWSPAPER IN IOWA USED BLIZZARD TO DESCRIBE A SNOWSTORM SOON BLIZZARD BECAME THE COMMON TERM FOR A MAJOR SNOWSTORM 6
7 EXPLORE MORE NOT ALL SNOWSTORMS ARE BLIZZARDS AND NOT ALL BLIZZARDS ARE ACCOMPANIED BY FALLING SNOW SOMETIMES STRONG WINDS BLOW AROUND SNOW THAT HAS ALREADY FALLEN CREATING A BLIZZARD THE BLOWING SNOW CAUSES THE SAME BLINDING UNSAFE CONDITIONS AS FALLING SNOW VISIBILITY THE ABILITY TO SEE OR BE SEEN
All air contains water vapor When air rises into the upper atmosphere it cools The water vapor begins to change into tiny drops of water which collect around bits of dust Water drops and dust are what clouds are made of As the temperature in the cloud dips several degrees below freezing the small water drops turn into tiny ice crystals These ice crystals stick together until they form snowflakes 8
9 SNOW AND WATER When snowflakes get bigger they become heavier and fall out of the douds If the air gets warmer as the snowflakes fall they melt and turn into rain If the air stays cold the snowflakes fall to the ground as snow Different types of snow contain different amounts of water For example if you melted 10 inches 25 cm of snow it could result in anywhere from less than an inch 2.5 cm to as much as 3 inches 7.6 cm of liquid water Generally the colder the air temperature and ground temperature the drier the snow will be CONDENSATION PRECIPITATION RAIN SNOW EVAPORATION GLACIER TRANSPIRATION OCEAN STREAM RIVER LAKE GROUNDWATER SNOWFALL IS PART OF THE WATER CYCLE OR THE MODEL SCIENTISTS USE TO SHOW HOW WATER MOVES BETWEEN EARTH UNDERGROUND AND THE ATMOSPHERE
