The 2006 storms in Vancouver were a series of storms in November 2006 that caused landslides into Vancouver's three main reservoirs. This led to the water system becoming contaminated far beyond the legal safety limit and forced the city to implement a boil water advisory for all of the city's two-million residents for more than a week—the largest such advisory in Canadian history. The advisory affected the local food industry, forcing supermarkets and restaurants to stop selling produce which couldn't be safely washed, and causing the majority of the city's many coffee shops to close. Although no dangerous bacteria levels were observed, the water was still considered unclean and unsafe to drink, wash vegetables or brush teeth with, without boiling it first for at least 1 minute. Bottled water was in high demand and became scarce in many areas. The storms were caused by an Aleutian Low's steering current, which allowed low pressure areas from the central subtropics of the North Pacific Ocean to track northeast and near areas of British Columbia, sometimes bringing more than 100 mm (4 in) of rain from each low. The low pressure systems were replaced by an Arctic ridge, which caused temperatures to dip to -12°C.