Winter storm

A winter storm is when wind blows together with precipitation that only happens when it's very cold, like snow, a mix of snow and rain, or freezing rain. These storms usually happen in places with cold climates, such as areas far from the equator. While they are most common in winter, they can also appear in late autumn or early spring.

When a snowstorm has very strong winds and you can't see far ahead, it is called a blizzard. Winter storms can change how we live for a while, making roads slippery and sometimes stopping people from traveling. Understanding winter storms helps us stay safe and prepare for the cold, snowy weather.

Formation

Winter storms happen when warm, moist air rises high into the atmosphere. This rising air creates low pressure near the ground and forms clouds. Hills or big mountains can also push the air upward. The wind picks up moisture from large bodies of water like lakes or oceans. If the temperature is below freezing, which is 0 °C (32 °F), the moisture falls as snow, ice, rain and snow mixed, ice pellets, or even graupel, which is soft hail. Cold air can't hold as much moisture as warm air, so less rain or snow falls during winter storms.

In the United States of America, winter storm warnings are issued under certain conditions. These include when snow builds up to certain amounts, when blowing snow makes it hard to see, when ice builds up on surfaces, when large ice pellets form, or when the wind chill gets very cold for several hours with steady wind speed.

When snowstorms have very strong winds and very low visibility for several hours, they are called blizzards.

Terminology

Big winter storms can cover large areas for several days. Even if not all the area meets the exact conditions for a winter storm, the whole area might call the event a "storm." For example, a big winter storm in February 2021 brought snow and freezing temperatures as far south as Texas.

Snowstorm

Snowstorms are when a lot of snow falls during a storm. Even just 2 inches (5 centimeters) of snow can cause big problems for traffic and school buses because roads become slippery and hard to drive on. This is especially true in places where snow doesn't usually fall but sometimes gets a lot at once. In areas where snow is common, smaller amounts of snow usually don't cause as many problems because people are used to it and have ways to clear the roads.

Big snowstorms can be very dangerous. Six inches (15 centimeters) of snow can make some roads impossible to drive on, and cars can get stuck. More than 12 inches (30 centimeters) of snow, especially in warmer places, can make roofs cave in and cause power to go out. Heavy, wet snow can break tree branches and power lines. Even a few inches of dry snow can pile up very high if the wind is strong. These storms can make it very hard to see outside, and sometimes people can get stuck in their cars and need help to get out. It's important to stay safe and warm during snowstorms.

Freezing rain

Main articles: Ice storm and Freezing rain

Heavy freezing rain is one of the most dangerous kinds of winter weather. It happens when there is a warm layer of air above a cold area, and the ground is below freezing. This makes the rain turn to ice when it hits the ground.

Even a small amount of ice can cause big problems. Driving can become very unsafe, power lines can break, and crops can be damaged. For example, a big ice storm in 1998 affected parts of Canada and the United States, causing lots of damage and leaving many people without power for weeks. Other ice storms have also caused serious issues, like losing electricity and water, and breaking trees and power lines.

Preparing for winter storms

In places where winter storms happen, governments and health groups offer advice on how to get ready for bad weather. Tips include having enough food, water, medicines, and cleaning supplies for three days, keeping warm clothes, having a flashlight with extra batteries, staying updated on weather news, helping neighbors, and avoiding travel unless it’s really needed.