The list and the criteria of the dangerous and hazardous hydrometeorological

phenomena and of the sudden weather changes 

      Dangerous phenomena 

• Thunderstorms

• Storms and winds in gusts of 15 m/s and more

• Fog of 200 m and less visibility that lasts 3 hours and more

• Heavy rains with a precipitations amount of 15-49 mm accumulated in 12 hours

• Hail with diameter of 6-19 mm

• Heavy snowfalls with a precipitations amount of 7-19 mm accumulated in 12 hours

• Snowstorm with wind speed of more than 11 m/s, more than 3 hours

• Sleet deposits with diameter of 11-34 mm

• Glazed frost with diameter of 6-19 mm

• Icy roads

• Heat waves – air temperature of +33°C and more

      Hazardous phenomena 

• Storms and winds in gusts of 25 m/s and more

• Heavy rains with a precipitations amount of 50 mm and more, accumulated in 12 hours, or with a precipitations amount of 30 mm and more, accumulated in 1 hour

• Long lasting rains with a precipitations amount of 120 mm and more, accumulated in 1-3 days

• Heavy hail with diameter of 20 mm and more

• Heavy snowfalls with a precipitations amount of 20 mm and more accumulated in 12 hours

• Snowstorm accompanied by snow drifting

• Fog of 50 m and less visibility that lasts more than 24 hours

• Glazed frost with diameter of 20 mm and more

• Ground frosts – negative air temperatures at a 2 m height and at the soil surface during the vegetation period

• Severe frost – air temperature of -25°C and less

• Exceptional fire risk 

Sudden weather changes

• Decrease of the maximum or minimum air temperature by 10°C and more during the cold period of the year

• Decrease of the air temperature by 10°C and more in 6-12 hours

• Replacement   of the   period   without  precipitations  (3-5 days  and  more)  with  a  period  with precipitations  (3-5 days and more) and vice versa.