Winter Storms (AMI Day 1) Just like any other storm at other times of the year, the right combination of ingredients is necessary for a winter storm to develop. Three basic ingredients are necessary to make a winter storm: cold air, lift and moisture. -Cold air. Below freezing temperatures in the clouds and near the ground are necessary to make snow and/or ice. -Lift. Something to raise the moist air to form the clouds and cause precipitation. An example of lift is warm air colliding with cold air and being forced to rise over the cold dome. The boundary between the warm and cold air masses is called a front. Another example of lift is air flowing up a mountainside. -Moisture. To form clouds and precipitation. Air blowing across a body of water, such as a large lake or the ocean, is an excellent source of moisture. A blizzard is a long-lasting snowstorm with very strong winds and intense snowfall. You need three things to have a blizzard; cold air at the surface, lots of moisture, and lift. Warm air must rise over cold air. Thundersnow is when thunder and lightning occur during a snowstorm. This occurs most often in late winter or early spring. To get thundersnow, you need a mass of cold air on top of warm air, plus moist air closer to the ground. Thundersnow starts out like a summer thunderstorm. The sun heats the ground and pushes masses of warm, moist air upward, creating unstable air columns. As it rises, the moisture condenses to form clouds, which are jostled by internal turbulence. The “tricky part” for making thundersnow is creating that atmospheric instability in the wintertime. For thundersnow to occur, the air layer closer to the ground has to be warmer than the layers above, but still cold enough to create snow. During thundersnow events, heavy snowfall is to be expected. In some cases, two inches per hour is possible. Thundersnow is when thunder and lightning occur during a snowstorm. This occurs most often in late winter or early spring. To get thundersnow, you need a mass of cold air on top of warm air, plus moist air closer to the ground. Thundersnow starts out like a summer thunderstorm. The sun heats the ground and pushes masses of warm, moist air upward, creating unstable air columns. As it rises, the moisture condenses to form clouds, which are jostled by internal turbulence. The “tricky part” for making thundersnow is creating that atmospheric instability in the wintertime. For thundersnow to occur, the air layer closer to the ground has to be warmer than the layers above, but still cold enough to create snow. During thundersnow events, heavy snowfall is to be expected. In some cases, two inches per hour is possible. -Sleet is just rain drops that freeze into ice pellets before reaching the ground. Sleet usually bounces when hitting a surface and does not stick to objects. However, it can accumulate like snow and cause a hazard to motorists. -Freezing rain is just rain that falls onto a surface with a temperature below freezing. This causes it to freeze to surfaces, such as trees, cars, and roads, forming a coating or glaze of ice. Even small accumulations of ice can cause a significant hazard. -Graupel (a.k.a. soft hail or snow pellets) are soft small pellets of ice created when supercooled water droplets coat a snowflake. -An ice storm is a type of winter storm caused by freezing rain. The U.S. National Weather Service defines an ice storm as a storm which results in the accumulation of at least 0.25-inch of ice on exposed surfaces. -Frost is white ice crystals that form on a surface, like the ground or leaves of a plant. Frost is created when the air temperature drops below freezing and the water vapor in the air freezes into ice crystals. Frost quakes are non-tectonic seismic events, meaning they are not caused by the shifting of the Earth’s tectonic plates. Also known as cryoseisms, frost quakes are caused by a sudden rapid freezing of ground and bedrock, usually when temperatures go from above freezing to below zero. As moisture absorbed in the rock and soil freezes, it expands. This puts a great amount of stress on the areas around it. Eventually, the stress is too much and the soil and rock will crack in an “explosive” manner, creating a loud sound and even shaking the ground surface. Since temperatures are coldest in the overnight hours, most people experience frost quakes in the middle of the night. An avalanche is a moving mass of snow that may contain ice, soil, rocks, and uprooted trees. The height of a mountain, the steepness of its slope, and the type of snow lying on it all help determine the likelihood of an avalanche. Avalanches begin when an unstable mass of snow breaks away from a mountainside and moves downhill. The growing river of snow picks up speed as it rushes down the mountain. Avalanches have been known to reach speeds of 245 miles an hour (394 kilometers per hour)—about four times as fast as the speediest downhill skier. Choose only the questions/answers from classes you currently have: 1. Math: Avalanches occur at 245 miles an hour. 245 miles an hour is four times as fast as the fastest downhill skier. What is the speed of the fastest downhill skier rounded to the nearest mph? A) 60 mph B) 61 mph C)62 mph D) 63 mph 2. English: In the paragraph about frost quakes the word “explosive” is put in quotation marks? Based on the sentences around it, what is the likely meaning of this word in the sentence? A) Destructive and devastating. B) Shaking uncontrollably and causing tsunamis. C) Noisy and moving the ground some. D) Similar to dynamite. 3. Health/PE: What would be the best way to exercise after 6 inches of snow has fallen? A.) Football B) Baseball C)X-Box D) Shoveling the driveway 4. Science: An ice storm is caused by_____________? A.) frost B). freezing rain C) sleet D) thunder snow 5. Social Studies: Based on the chart above, where must the below freezing temperature be in order for freezing rain to occur? A) lower and middle B) middle and upper C) middle only D) lower and upper 6. Agri/Career: What type of winter precipitation would be worst for a cattle farmer? A) Snow B) Sleet C) Thunder Snow D) Freezing Rain/Ice 7. Music: In the Disney Movie “Frozen”, what is the song Elsa is singing while she creates her Ice Castle? A) Let it Go B) In Summer C) Fixer Upper D) Frozen Heart 8. Spanish: What is the term for snow in Spanish? A) La sequia B) La lluvia C) La nieve D) El viento .