Thunderstorm warnings are only issued for categories 3 and 4.

A thunderstorm event that is usual for the time of year (for which, therefore, no special warnings are issued).

• Effects:
  • Flash flooding of streams
  • Toppling of trees
  • Possibility of localised landslides on steep slopes
  • Damage from hail and lightning strikes
  • Failure of drainage and sewer systems.
  • Flooding of underpasses, underground garages and cellars.
  • Disruption to road, rail and air traffic
  • Danger to vessels on lakes from very strong gusts of wind arising rapidly without warning
• Behaviour:
  • Keep an eye on local weather developments
  • Seek shelter of lightning strikes, hail or storms
• Description of measurement and prognostic values:
  • Severe thunderstorm (flash thunderstorm; localised, warning time 0 to 2 hours): 90-120 km/h, 2-4 cm (hailstones), 30-50 mm/h

• Effects:
  • Flash flooding of streams
  • Toppling of trees
  • Possibility of localised landslides on steep slopes
  • Damage from hail and lightning strikes
  • Failure of drainage and sewer systems.
  • Flooding of underpasses, underground garages and cellars.
  • Disruption to road, rail and air traffic
  • Danger to vessels on lakes from very strong gusts of wind arising rapidly without warning
• Behaviour:
  • Keep an eye on local weather developments
  • Seek shelter of lightning strikes, hail or storms
• Description of measurement and prognostic values:
  • Very severe thunderstorm (flash storm, local; warning time 0 to 2 hours): > 120 km/h, >4 cm hailstones, >50 mm/h

Thunderstorm warnings are only issued for categories 3 and 4.

No evaluation.