Expats in Holland need to be aware of weather alerts issued by KNMI (Royal Dutch Weather Bureau), what they mean and how they are communicated to residents in Netherlands.
The KNMI (Koninklijk Nederlands Meteorologisch Instituut or ‘Royal Netherlands Meteorological Institute’) is the official Dutch weather bureau. It is a government agency within the Ministry of Infrastructure and Water Management.
One of the organizations’s main responsibilities is to monitor conditions and communicate a weather alert to residents whenever a potential dangerous condition is forecast. This could be in the form of rain, snow, ice, lightning, wind, temperature or visibility.
KNMI Weather Color Warnings
The KNMI issues weather color warnings by province and specific regions, such as the Ijsselmeer and the Wadden Islands, but only if the impacted area is larger than 50 square kilometers.
GREEN is an indication that seasonally normal weather is expected (no warning)
YELLOW indicates to be ‘on alert’ for a potential dangerous weather occurrence. A yellow warning can be issued up to 48 hours in advance if the weather event has a 60% or higher chance of occurrence.
ORANGE indicates to ‘be prepared’ for a hazardous extreme weather condition where there is a chance of damage, injury or nuisance. Often these can be very localized. An orange warning is issued 24 hours in advance if there is a 60% or higher chance of probability.
RED indicates a severe weather alert for a situation that can be expected to cause substantial nuisance, injury and damage to property and infrastructure. It is issued a maximum of 12 hours before the expected weather event.
WEATHER WARNING COLOR DETAILS
|TYPE / COLOR||YELLOW||ORANGE|
30+ mm/hr, or 50+ mm in 24 hrs
|75+ mm over 24 hrs|
|THUNDERSTORM||1 lightning strike in 5 mins (with or without hail)||500 lightning strikes in 5 mins (with or without hail)|
|WIND||Gusts over 75kph (over 90kph along coast in winter)||Gusts 100+ kph (120+kph along coast in winter)|
|TEMPERATURE||Over 35C or below -15C, 4 consecutive days of 27C +|
|VISIBILITY||Less than 200 m||Less than 10 m|
Weather Warning Communication
When the KNMI issues a code orange warning or code red alarm, it sends it out on Twitter (@knmi) as well as on NOS teletext (P. 710).