What Is a Snowband?
A snowband is a relatively narrow area where snowfall becomes concentrated. Snow within the band can be much heavier than in surrounding areas, creating large differences in accumulation over short distances.
Snowbands can vary considerably in size and intensity. Some produce moderate snow, while stronger bands can produce heavy snowfall and rapidly reduce visibility.
They are especially common during lake-effect snow events, when wind and atmospheric conditions organize snowfall into narrow bands extending downwind from a lake.
Related Conditions
| Condition | Description |
|---|---|
| Lake-Effect Snow | Snow that develops when cold air moves across relatively warmer, open lake water. |
| Snow Squall | A sudden period of heavy snow that can quickly reduce visibility and cover roads. |
| Heavy Snowfall | Snowfall that produces significant accumulation over a relatively short period. |
| Snow | Frozen precipitation that forms as ice crystals in clouds and falls as snowflakes. |
| Whiteout | A condition where snow and poor visibility make surrounding features difficult or impossible to see. |
Related Alerts
| Alert | Description |
|---|---|
| Snow Squall Warning | Warns of snow squalls that can cause sudden poor visibility and hazardous travel. |
| Snowfall Warning | Issued when significant snowfall is expected to meet warning criteria for an area. |
| Winter Storm Warning | Warns of a significant combination of hazardous winter weather. |
| Winter Storm Watch | Alerts people to the potential for significant winter weather to develop. |
| Blowing Snow Advisory | Issued when blowing snow is expected to significantly reduce visibility. |
What Causes a Snowband?
A snowband forms when atmospheric conditions concentrate rising air and moisture into a relatively narrow area. This allows snow-producing clouds to become organized rather than producing snowfall evenly across a wider region.
One common example occurs during lake-effect snow. Cold air passing across relatively warmer lake water gains heat and moisture. Under the right wind conditions, this moisture can become organized into a narrow band of clouds and snowfall extending downwind of the lake.
Wind direction plays an important role in determining where a snowband develops and how long it remains over one location. A small change in wind direction can shift a band and move the heaviest snowfall into a different community.
If a snowband remains over the same area for several hours, snowfall can accumulate quickly. This is one reason neighbouring communities can receive very different snowfall totals from the same weather event.
Some snowbands can also become intense enough to produce sudden reductions in visibility and hazardous road conditions. Meteorologists use radar to identify these concentrated areas of snow and track how they develop and move. Our guide to how Doppler radar works explains how radar is used to observe precipitation.
FAQ
On weather radar, a snowband often appears as a relatively narrow area of more concentrated precipitation. At ground level, it may appear as a distinct area of heavier snow surrounded by lighter snowfall.
There is no single width for a snowband. Some can be relatively narrow, while others extend across a much larger area depending on the weather system producing them.
Snowbands concentrate moisture and rising air into a smaller area. If a band remains over the same location, snow can continue falling there while nearby areas receive much less.
No. Lake-effect snow is one process that can produce snowbands, but bands of concentrated snowfall can also develop within other weather systems.
Meteorologists use weather radar, satellite observations, surface reports and weather models to determine where snowbands are forming and where they are likely to move.