Top ten weather stories for 2005: story one
1. Alberta's Flood of Floods
Though spring was dry across southern Alberta - some 50% drier than normal - farmers and ranchers were not overly concerned. Fall and winter together had been wetter than normal, and June is often the wettest month of the year. For 2005 it couldn't have been more true! June was so wet that by the end, several communities had gone through their wettest month ever.
Three major storms about a week apart drenched the region, generating record high water levels. Rivaling historic floods, rain-swollen streams burst their banks, inundating southern Alberta towns and forcing thousands of residents to evacuate. At High River, rising waters forced residents out of their homes on at least two occasions, some being airlifted by helicopter. Floodwaters washed out roads and parks, destroyed sewers, bridges and other infrastructure, wrecked buildings and drowned livestock. In Calgary, one in ten dwellings reported damage. Insurance losses were staggering and, together with uninsured infrastructure, could easily top $400 million, including $275 million in insured losses -- making it one of the costliest natural disasters in Alberta's history.
About 40 municipalities identified infrastructure damage and fourteen declared official states of emergency. Four people lost their lives - two when they were swept away by turbulent waters and two others when vehicles plunged into swollen rivers.
While the moist weather systems were not unusual, they stalled and even tracked westward instead of following their usual west-to-east movement. What became a real blessing was the previous winter's lack of snowfall in the southwest foothills (the lowest in four decades), which left little melt water to add to the pouring rain. Still, many rivers such as the Bow, Oldman and Red Deer were engorged, flowing 10 to 30 times their usual volume. Hydrologists estimated the flooding as a 1-in-200-year occurrence. Fortunately, dams and other hydrologic structures helped to limit some of the damage. Without them, Drumheller would have looked like New Orleans after Katrina.
In Calgary, June was the wettest month ever recorded. Total rainfall was 247.6 mm compared to a normal of 79.8 mm. Outside the city, monthly rainfalls approached 400 mm. When the Glenmore Reservoir overflowed for the first time in memory, the normally placid Elbow River peaked about ten times its usual June flow, prompting unprecedented evacuation plans for numerous riverside communities. More than 2,000 Calgary residents, from millionaires to boarders, abandoned their residences. Floodwaters filled basements to the ceiling with foul-smelling, raw sewage. Concern was also raised over Calgary's supply of clean water. By the opening of the Calgary Stampede, Southern Albertans had seen enough rain to last a lifetime.
- Date modified: