In the spring, inland flooding can occur with rapid snowmelt and heavy rainfall. Flooding can also be caused by water backing up behind an ice jam. At other times of the year, intense rainfall during major storms can cause flash flooding, particularly in smaller rivers.
Coastal flooding can be caused by unusually high tides or storm surges. The land close to an area of brackish water or estuary can be at particular risk of flooding due to high water levels caused by high river flows, marine tides and storm surges which can act alone or in combination.