hällregn

Hällregn is a Swedish meteorological term used to describe a form of precipitation characterized by very heavy rainfall that falls in a short period. The phenomenon is typically associated with convective weather systems and is often linked to thunderstorms or rapid air mass lifting. In weather forecasts and warnings issued by SMHI, hällregn is cited as intense rain that can lead to rapid water accumulation on roads and surfaces, creating hazardous driving conditions and localized flooding.

Key features of hällregn include high rainfall intensity and short duration, with rain falling in strong bursts rather than as a steady drizzle. The effect is usually localized, affecting urban areas or neighborhoods rather than entire regions. Visibility can deteriorate quickly and drainage systems may become overwhelmed if the rain persists long enough.

Meteorologically, hällregn arises from convective processes where warm, moist air rises vigorously, producing tall cloud development and heavy raindrop formation. These events are most common in warmer seasons, often accompanying thunderstorm activity, though the exact shape and duration of a hail-free downpour can vary.

Impact and safety considerations include the potential for flash flooding in low-lying areas, slick road surfaces, and reduced visibility for motorists and pedestrians. People are advised to seek shelter during thunderstorms and to exercise caution if travel is necessary during or shortly after a hällregn event.

See also: thunderstorm, convective precipitation, rainfall intensity, hail (hagel).