What is snow? Plain-English meaning

Short definition: Snow is frozen precipitation that falls from clouds as ice crystals and accumulates on the ground when temperatures are cold enough.

Plain-English explanation

Snow forms when water vapor in the air freezes into ice crystals inside clouds, and those crystals grow and stick together until they are heavy enough to fall. Each snowflake is a collection of many ice crystals, and its shape depends on temperature and humidity. When snow reaches the ground, it can pile up and create a snowpack that lasts for days or months. Snow is an important part of the water cycle because it stores water in winter and releases it when it melts in spring. The amount and timing of snowfall affect water supplies, winter sports, travel, and ecosystems.

Why it matters

Snow matters because it affects daily life in cold regions and provides water for many communities. Understanding snow helps you interpret weather forecasts, prepare for winter driving, and know why some winters are snowier than others. It also helps you understand how climate and weather interact, since snow cover reflects sunlight and influences temperature.

Concrete example

In a winter storm, a weather forecast calls for 15 centimeters of snow. As the storm passes, snow accumulates on roads and sidewalks, and people need to shovel or use snowplows. When spring arrives, that snow melts and flows into rivers and reservoirs, providing water for cities and farms downstream.

Common confusion

People often confuse snow with sleet or freezing rain. Sleet is small ice pellets that bounce when they hit the ground, while freezing rain is liquid rain that freezes on contact with cold surfaces. Snow is always made of ice crystals and remains frozen as it falls.

Related terms

precipitation, ice crystals, snowpack, blizzard, water cycle

How people actually use it

People use snow for recreation such as skiing and snowboarding, and it is essential for water storage in mountainous regions. Snowfall forecasts are used for road maintenance, school closures, and avalanche warnings.

Related terms explained

ice crystal

An ice crystal is a solid form of water with a regular hexagonal structure. Snowflakes are composed of many ice crystals that grow as they fall through clouds.

Example: Under a microscope, a snowflake shows a symmetrical six-sided ice crystal pattern.

avalanche

An avalanche is a rapid flow of snow down a slope, often triggered by snowfall, temperature changes, or human activity. They can be dangerous to people and infrastructure in mountainous areas.

Example: Skiers avoid steep slopes after heavy snowfall to reduce the risk of triggering an avalanche.

albedo

Albedo is the fraction of incoming solar radiation reflected by a surface. Snow has a high albedo, reflecting most sunlight, which helps keep the Earth cool.

Example: Fresh snow has an albedo of about 0.8 to 0.9, reflecting 80 to 90 percent of sunlight.

snowpack

Snowpack is the accumulated snow on the ground over a season. It acts as a natural reservoir, releasing water slowly when it melts in spring.

Example: The mountain snowpack provides water for downstream cities during the dry summer months.

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More context

Snow forms through the Bergeron process, where ice crystals grow at the expense of supercooled water droplets in mixed-phase clouds. The six-sided symmetry of snowflakes results from the molecular structure of ice, and no two flakes are identical at the microscopic level due to varying temperature and humidity paths. Snowpack acts as a natural water reservoir, supplying meltwater to rivers and aquifers in spring, which is vital for agriculture in many regions.

Additional background

Snow forms in clouds when water vapor deposits directly into ice crystals on tiny particles called ice nuclei. These crystals grow as they collide with supercooled water droplets, which freeze onto them. The classic six-pointed star shape emerges because of the molecular structure of ice. Snowflakes can be simple prisms, needles, plates, or complex dendrites, depending on the temperature and humidity they encounter. Once on the ground, snow undergoes metamorphism, changing its crystal structure over time due to pressure and temperature gradients. This process affects the snow's density and stability, which is critical for skiers and avalanche forecasters. Snow also plays a role in Earth's albedo, the measure of how much sunlight is reflected, and changes in snow cover can influence global climate patterns.