Why five centimetres of snow can be harmless or cause chaos: Latvian weather expert explains how warnings are made
Latvian forecasters base weather warnings not only on meteorological measurements but also on expected impact on daily life, as explained by LVĢMC's Kristiāns Pāps.
The head of the Forecast Department at the Latvian Environment, Geology and Meteorology Centre, Kristiāns Pāps, has explained on the TV24 programme "Uz līnijas" how weather warnings are prepared in Latvia. The system, similar to other European countries, takes into account both weather forecasts and the possible effect on people's safety and routines.
A yellow warning generally means conditions may not yet be dangerous but could disrupt everyday activities. An orange warning points to more hazardous conditions, prompting people to consider changing their plans or whether to go out at all. A red warning is the highest level, indicating that it is best to stay indoors.
Pāps also addressed a common misconception. If an orange or red warning is issued for a region, it does not mean that every location within it will experience dangerous weather. Thunderstorms in particular can be very localised, with a storm in one place and sunshine nearby. Therefore warnings specify whether the phenomenon is expected in places or across most of the region.
Preparing warnings is one of the forecasters' most responsible tasks. They analyse forecast models, various scenarios and threshold values, as well as the territory likely to be affected. But figures alone are insufficient. The same weather can have completely different consequences depending on circumstances. As an example, Pāps mentioned snowfall. Five centimetres of snow on a calm January night, when people are used to it and roads are regularly cleared, may have little impact. The same amount late in autumn or at the beginning of winter, especially during Monday morning rush hour, can be enough to cause chaos. In such conditions, even two or three centimetres may lead to accidents.
The key, therefore, is to assess not only how hard it will snow, rain or blow, but also how the weather will affect people at that particular moment.
