A 51-year old woman died in Haarlem after a tree fell on the car she was in, local police said.

In Amsterdam, several people were injured as dozens of trees were toppled by the storm, damaging cars and houseboats along the city’s canals.

The National Meteorology Institute sent its highest code red storm warning to residents of the Noord-Holland province, which includes Amsterdam, urging them not to leave their homes and to note emergency service numbers for life-threatening situations only.

The storm, named Poly, is the Netherlands’ worst ever during the summer months and its strongest overall since January 2018, weather agency Weeronline said.

Heavy storms in the Netherlands usually occur between October and April. The last heavy summer storm was in 2015 and was the first in over a century.

The summer storm is causing much damage as trees are heavy with leaves and many of them have become brittle during an unusually long dry spell in May and June.

Amsterdam’s Schiphol airport, one of Europe’s busiest hubs, cancelled more than 400 flights, a spokesperson said, with traffic expected to be limited until at least 4 pm local time (1400 GMT).

Train operators NS and Arriva halted all services in the country’s north, and a highway north of Amsterdam was closed due to falling trees.

The storm will move east over the north of the country and is expected to become less intense during the afternoon.

(Reporting by Bart Meijer and Toby Sterling; Editing by Andrew Heavens, Jan Harvey, John Stonestreet, Alexandra Hudson)