What Is a Whiteout?
A whiteout is a condition where visibility and contrast become so poor that the horizon and surrounding features are difficult or impossible to see. The ground and sky can appear to blend together, making it difficult to judge distance or direction.
Whiteouts are commonly associated with heavy falling snow and blowing snow. They can develop during snow squalls, blizzards and other winter weather where large amounts of snow are moving through the air.
Whiteout conditions can be especially dangerous for drivers. Roads, vehicles, signs and lane markings can become difficult to see, sometimes with little warning.
Related Conditions
| Condition | Description |
|---|---|
| Blowing Snow | Loose snow lifted and carried by wind, often reducing visibility. |
| Ground Blizzard | Blizzard conditions caused mainly by strong winds lifting snow already on the ground. |
| Snow Squall | A sudden period of heavy snow that can quickly reduce visibility and cover roads. |
| Heavy Snowfall | Snowfall that produces significant accumulation and can greatly reduce visibility. |
| Snow | Frozen precipitation that can reduce visibility when falling heavily. |
Related Alerts
| Alert | Description |
|---|---|
| Snow Squall Warning | Warns of snow squalls that can cause sudden near-zero visibility and hazardous travel. |
| Blizzard Warning | Warns of strong winds and blowing snow producing severely reduced visibility. |
| Blowing Snow Advisory | Issued when blowing snow is expected to significantly reduce visibility. |
| Snowfall Warning | Issued when significant snowfall is expected to meet warning criteria for an area. |
| Winter Storm Watch | Alerts people to the potential for significant winter weather to develop. |
What Causes a Whiteout?
A whiteout develops when there is so little contrast between the sky, snow-covered ground and surrounding objects that it becomes difficult to tell them apart. The horizon may disappear, and without clear reference points it can become difficult to judge distance or direction.
One common cause is heavy snowfall. When enough snow is falling through the air, it can block the view of roads, buildings and other objects. An intense snow squall can cause visibility to deteriorate particularly quickly.
Strong winds can create whiteout conditions even when little or no new snow is falling. During blowing snow, loose snow already on the ground is lifted into the air and carried by the wind. If enough snow is present, visibility can fall dramatically.
Cloud cover and lighting can make the problem worse. When the sky and snow-covered ground have similar brightness, shadows and contrast can disappear. This makes hills, dips and other features in the snow harder to recognize.
Whiteout describes the visibility conditions rather than one particular type of storm. This means it can occur during several different winter weather events. If you are caught in one, our guide on what to do during a whiteout covers the steps to take.
FAQ
During a whiteout, the sky and snow-covered ground can appear to blend together. The horizon may disappear, while roads, objects and changes in terrain become difficult to see.
It depends on the severity of the conditions. During an intense whiteout, visibility can fall to a very short distance or become near zero.
Yes. Whiteouts can make driving and outdoor travel dangerous because it becomes difficult to see obstacles, judge distances or determine direction.
A whiteout describes a loss of visibility and contrast. A blizzard is a winter weather condition involving strong winds and severely reduced visibility in snow or blowing snow for a sustained period.
Yes. Strong winds can lift snow that is already on the ground and create whiteout conditions even when no new snow is falling.
Yes. A snow squall can produce intense falling snow and gusty winds that cause visibility to drop very quickly.
Whiteout conditions can last for only a few minutes during a passing snow squall or continue for hours during a larger winter storm or prolonged blowing snow event.
Avoid travelling in whiteout conditions when possible. If visibility suddenly deteriorates while you are already driving, slow down, increase your following distance and follow official weather and travel guidance.