A snow squall is a brief but intense burst of heavy snow accompanied by strong, gusty winds. Snow squalls have warning systems in place to alert the public. Wind speed and direction play roles in the formation and movement of snow squalls. Visibility during a snow squall drops, creating hazardous conditions. Understand the definition, warning process, wind characteristics, and visibility impacts of snow squalls to stay safe during these winter weather events.
Snow squalls are bursts of heavy snowfall lasting minutes to an hour. Snow squalls produce accumulations of amounts in short periods. Snow squalls form due to air mass movement and rising, cooling, and condensing air. Snow production rates reach 2-3 inches (5-7.5 cm) per hour during snow squalls.
Canada holds the title of “Snow Squall Capital of the World,” experiencing 20-30 snow squalls per year. The United States faces snow squall activity, with Lake Ontario seeing 10-15 snow squalls annually. Japan encounters 10-20 snow squalls, with Hokkaido facing 5-8 yearly. Russia’s territory leads to 20-30 snow squalls, with Murmansk Oblast experiencing 5-8 yearly. Finland experiences 10-20 snow squalls, with Lapland encountering 5-8 and Eastern Finland facing 3-5. Norway’s geography results in 5-10 snow squalls per year, with Western Norway experiencing 3-5 and Northern Norway facing 2-3. Sweden’s position leads to 5-10 snow squalls per year, with Northern Sweden encountering 3-5 and Swedish Lapland experiencing 2-3. Iceland’s location causes 2-5 snow squalls per year, with Northern and Eastern Iceland facing 1-2 yearly.
What is the definition of a snow squall?
Snow squalls last 30 minutes to 1 hour, producing snowfall rates of 1-3 inches (2.5-7.6 cm) per hour. Snow squalls reduce visibility to less than 1/4 mile (400 meters) for a period. Snow squalls occur in areas prone to lake-effect snow, such as the Great Lakes region in North America, and in mountainous regions. Snow squalls form when cold air passes over a body of warmer water or when a strong cold front interacts with a mass of moist air.
What is a snow squall warning?
Snow squalls produce snowfall rates of up to 2-3 inches (5-7.5 cm) per hour. Strong winds of 30-40 mph (48-64 km/h) or higher accompany these intense snow bursts. Visibility reduces to less than 1/4 mile (400 meters) during snow squalls. Poor visibility conditions last for 30 minutes to an hour. Meteorological agencies issue snow squall warnings when snow squalls have the potential to develop, lasting 1-2 hours.
Snow squall warnings are alerts issued by the National Weather Service to protect life and property from hazardous winter weather conditions. Forecasters issue snow squall warnings when conditions include snowfall rates of 1-2 inches (2.54-5.08 cm) per hour, winds over 35 mph (56.33 km/h), and visibilities under 1/4 mile (0.4 km). Snow squall warnings cover specific polygonal areas and last 30-60 minutes, similar to thunderstorm or tornado warnings. The National Weather Service disseminates snow squall warnings through channels including NOAA Weather Radio, wireless emergency alerts on mobile devices, social media, weather apps, and news outlets. Snow squall warning products provide information on affected areas, expected duration, wind speeds, visibility levels, and snowfall rates.
Snow squall warning alerts trigger emergency messages across platforms to reach the public. The content of a snow squall warning includes details on the locations impacted, timing of the squall, expected wind speeds, visibility reductions, and snowfall intensity. Snow squall warnings focus on localized areas experiencing bursts of heavy snow and strong winds. These targeted warnings allow the National Weather Service to provide precise alerts compared to broader winter storm warnings. Snow squall warnings advise the public to avoid travel until the dangerous conditions pass due to hazards like whiteout conditions and icy roads.
What is the difference between a snowsquall and a blizzard?
Snow squalls are winter weather events characterized by heavy snowfall and gusty winds. Blizzards are periods of heavy snowfall and strong, sustained winds lasting at least three hours. Snow squalls create whiteout conditions for a duration, ranging from minutes to an hour. Blizzards reduce visibility to less than 1/4 mile (400 meters) for a period. Winds in blizzards exceed 35-40 mph (55-65 km/h), while snow squalls feature localized, short bursts of intense wind.
The difference between a snowsquall and a blizzard is explained in the table below.
| Aspect | Snowsquall | Blizzard |
| Definition | Characterized by heavy snowfall and gusty winds, creating brief whiteout conditions with visibility < 1/4 mile (400 meters) and wind gusts up to 50 mph (80 km/h). | A period of heavy snowfall and strong, sustained winds lasting at least 3 hours with visibility < 1/4 mile (400 meters) and sustained winds ≥ 35 mph (55 km/h). |
| Duration | Lasts from 15 minutes to 1 hour. | Persists for at least 3 hours, with some events lasting up to 12 hours. |
| Wind Speed | Localized, short bursts of intense wind with gusts up to 50 mph (80 km/h). | Winds exceed 35-40 mph (55-65 km/h) with frequent gusts ≥ 50 mph (80 km/h). |
| Visibility | Creates whiteout conditions with visibility < 1/4 mile (400 meters) for 15 minutes to 1 hour. | Reduces visibility to < 1/4 mile (400 meters) for at least 3 hours. |
| Warning Time | Develop quickly with warning times < 30 minutes. | Have longer forecast lead times, typically 2-12 hours. |
| Impact Area | Affect localized areas, typically < 10 square miles (26 km²). | Impact larger regions, spanning entire states or areas up to 100,000 square miles (260,000 km²). |
| Snow Accumulation | Deposits 2-6 inches (5-15 cm) of snow in short periods. | Results in higher total accumulations, exceeding 6-12 inches (15-30 cm) with some events producing > 2 feet (60 cm). |
Snow squalls and blizzards differ in duration and intensity. Blizzards are sustained events persisting for at least three hours. Wind and visibility requirements distinguish these phenomena. Snow squalls have no wind speed or visibility criteria. Blizzards require winds exceeding 35-40 mph (56-64 km/h) and visibility below 1/4 mile (400 meters).
What causes a snow squall?
Snow squalls are sudden winter storms that produce strong winds and heavy snowfall. Whiteout conditions result from snow squalls, reducing visibility to near zero. Gusty winds in snow squalls reach speeds of 40-50 mph (64-80 km/h). Snow squalls occur when a mass of cold air moves into an area, causing the air to rise, cool, and condense. Fronts, including cold fronts or Arctic fronts, are associated with the occurrence of snow squalls.
The causes of a snow squall are outlined below.
- Snow squall weather formation: Occurs due to cold air mass movement and rising, cooling, and condensing air.
- Snow squall wind conditions: Produces gusty winds up to 40-50 mph (64-80 km/h).
- Snow squall visibility impact: Causes whiteout conditions with near-zero visibility.
- Snow squall frontal systems: Associated with fronts, including cold fronts and Arctic fronts.
- Snow squall air temperature contrast: Triggered by Arctic air masses interacting with warmer regions.
- Snow squall over water: Intensified by cold air passing over warm lakes or oceans.
- Snow squall convective clouds: Formed due to temperature differences between cold air and warm water.
- Snow squall atmospheric dynamics: Involves cold fronts providing lift for moisture rising and condensing.
- Snow squall snowfall rate: Results in snow production rates of 2-3 inches (5-7.5 cm) per hour.
- Snow squall travel hazards: Rapidly develops whiteout conditions with less than 1/4 mile (400 meters) visibility.
- Snow squall temperature effects: Accompanied by temperature drops of 10-20°F (5-10°C) leading to icy roads.
Air movement plays a crucial role in snow squall formation. Arctic air masses push into warmer regions, creating temperature contrasts. Strong cold fronts advance, displacing warmer air and triggering intense snowfall. The interaction between cold air and warm waters intensifies snow squall development. Cold air passing over warm lakes or oceans picks up moisture and heat. Convective clouds form due to the temperature difference between the cold air and warm water surface.
Atmospheric dynamics contribute to snow squall intensity. Cold fronts provide lift for moisture to rise and condense. Sudden bursts of snow occur as the lifted air cools and forms ice crystals. The combination of these factors results in the features of snow squalls. Snow production rates reach 2-3 inches (5-7.5 cm) per hour. Gusty winds combine with snowfall, reducing visibility to less than 1/4 mile (400 meters). White out conditions develop rapidly, making travel hazardous. Temperature drops of 10-20°F (5-10°C) accompany snow squalls, producing icy roads within minutes.
What does a snow squall look like?
A snow squall looks like a sudden, intense burst of snowfall accompanied by strong, gusty winds that reduces visibility, creating whiteout conditions and accumulating snow. Snow squalls are characterized by weather phenomena, affecting localized areas. Heavy snowfall and gusty winds produce near-zero visibility, creating whiteout conditions. Snow accumulations of 1-3 inches (2.54-7.62 cm) occur within 30 minutes to an hour. Winds gusting up to 40-50 mph (64-80 km/h) accompany snow squalls, contributing to blowing and drifting snow.
Snow squalls are characterized by sudden and intense bursts of snowfall. Heavy snowfall rates reach up to 2-3 inches (5-7.6 cm) per hour during snow squalls. Visibilities decrease from several miles to a few hundred feet in minutes. Gusty winds accompany snow squalls, contributing to hazardous conditions. Snow squall winds gust up to 40-50 mph (64-80 km/h), leading to blowing snow and whiteout conditions. Blowing snow reduces visibility to less than 1/4 mile (400 meters) in minutes.
Snow squall clouds resemble thunderheads, appearing as anvil-shaped masses. Cumulonimbus clouds appear with flat bases and towering vertical growth up to 10,000 meters (32,808.4 feet) into the atmosphere. Snow squall look is characterized by defined edges, showing distinction from the surrounding environment. The sky darkens as snow squalls approach, turning grey. Snow squalls create a wall of snow, becoming impossible to see through. Weather forecasters issue snow squall warnings to alert travelers of danger and deteriorating conditions.
What is the biggest risk of a snow squall?
Snow squalls pose a threat to motorists despite accumulating less than 2.54 centimeters (1 inch) of snow. Gusty winds in snow squalls reach speeds of up to 40 mph (64.37 km/h), reducing visibility for drivers. Falling temperatures during snow squalls drop by 10°F (5.56°C) in minutes, contributing to ice formation on roads. Visibility decreases to near zero in 30 seconds to 1 minute, according to the National Weather Service. Snow squalls are responsible for an average of 200-400 fatalities per year in the United States, as reported by the National Weather Service.
The decline in visibility poses the greatest threat during snow squalls. Whiteout conditions create a wall of snow, obscuring roads and vehicles. Visibility goes down to near zero in minutes on highways, making it impossible to distinguish roads from surroundings. Driving conditions deteriorate when snow squalls hit. Travel becomes impossible during the peak intensity of snow squalls. Vehicles swerve or get blown off the road in snow squall conditions. Strong gusty winds reach speeds up to 50-60 mph (80.5-96.5 km/h) during snow squalls.
Snow squalls increase the risk of traffic accidents on highways. Vehicle speeds on highways amplify the danger during snow squalls. Chain-reaction pile ups are triggered by sudden loss of visibility in snow squalls. The National Weather Service reports snow squalls cause up to 30% of winter traffic fatalities. Drivers caught off guard by snow squalls have difficulty reacting in time. Pulling over to a safe place is crucial when encountering a snow squall while driving. Waiting for visibility and safe road conditions is advised during snow squalls.
What countries have the most snow squalls?
The countries with the most snow squalls are listed in the table below.
| Country | Region | Average Snow Squalls per Year | Average Duration | Average Visibility Reduction | Average Wind Speed |
| Canada | National | 22.5 | 2-4 hours | 200-500 meters | 40-60 km/h |
| United States | Great Lakes | 12.8 | 1-3 hours | 150-300 meters | 30-50 km/h |
| Japan | National | 15.2 | 1-2 hours | 100-200 meters | 25-40 km/h |
| Japan | Hokkaido | 6.5 | 30 minutes-1 hour | 50-100 meters | 20-30 km/h |
| Russia | National | 25.1 | 2-4 hours | 250-500 meters | 45-65 km/h |
| Russia | Murmansk Oblast | 6.8 | 1-2 hours | 100-200 meters | 30-45 km/h |
| Finland | National | 14.5 | 1-2 hours | 100-200 meters | 25-40 km/h |
| Finland | Lapland | 6.2 | 30 minutes-1 hour | 50-100 meters | 20-30 km/h |
| Finland | Eastern Finland | 4.1 | 30 minutes-1 hour | 20-50 meters | 15-25 km/h |
| Norway | National | 7.3 | 1-2 hours | 50-100 meters | 20-35 km/h |
| Norway | Western Norway | 4.5 | 30 minutes-1 hour | 20-50 meters | 15-25 km/h |
| Norway | Northern Norway | 2.8 | 30 minutes-1 hour | 10-20 meters | 10-20 km/h |
| Sweden | National | 7.8 | 1-2 hours | 50-100 meters | 20-35 km/h |
| Sweden | Northern Sweden | 4.9 | 30 minutes-1 hour | 20-50 meters | 15-25 km/h |
| Sweden | Swedish Lapland | 2.9 | 30 minutes-1 hour | 10-20 meters | 10-20 km/h |
| Iceland | National | 3.5 | 30 minutes-1 hour | 10-20 meters | 15-25 km/h |
| Iceland | Northern Iceland | 1.9 | 30 minutes-1 hour | 5-10 meters | 10-15 km/h |
| Iceland | Eastern Iceland | 1.7 | 30 minutes-1 hour | 5-10 meters | 10-15 km/h |
Countries that experience the most snow squalls include Canada, the United States (particularly the Great Lakes region), Japan, Russia, Finland, Norway, Sweden, and Iceland. Canada holds the title of “Snow Squall Capital of the World” with 20-30 snow squalls per year on average. The Great Lakes region in the United States faces significant snow squall activity, with Lake Ontario seeing 10-15 snow squalls annually. Japan’s terrain and location make it prone to 10-20 snow squalls annually, with Hokkaido encountering 5-8 snow squalls yearly. Russia’s vast territory leads to 20-30 snow squalls annually, with Murmansk Oblast facing 5-8 snow squalls yearly.
Finland experiences 10-20 snow squalls annually due to its location. Lapland encounters 5-8 snow squalls yearly, while Eastern Finland faces 3-5 snow squalls. Norway’s geography results in 5-10 snow squalls per year. Western Norway experiences 3-5 snow squalls, and Northern Norway faces 2-3 snow squalls. Sweden’s position leads to 5-10 snow squalls per year. Northern Sweden encounters 3-5 snow squalls, and Swedish Lapland experiences 2-3 snow squalls. Iceland’s location causes 2-5 snow squalls per year. Northern Iceland and Eastern Iceland both face 1-2 snow squalls yearly. Arctic countries share characteristics in snow squall occurrence due to their proximity to Arctic waters. Finland’s eastern and northern regions face over 10 snow squall events yearly. Norway’s western and northern regions encounter over 5 snow squall events annually. Sweden’s Norrbotten and Västerbotten provinces experience over 5 snow squall events yearly. Iceland’s northern and eastern regions face over 5 snow squall events annually.