Hail is precipitation consisting of ice pellets with a diameter of 5 millimetres or more. Hailstorms can occur anywhere in Canada. The most common period when hailstorms occur is from May to July, usually occurring with afternoon thunderstorms. Hailstorm with large hail pellets is spectacularly damaging. Smaller storms during the summer growing season cause serious damage to crops. This map shows some of the major hailstorms that happened in Canada since the beginning of the 20th Century to 1999.