2011 - a year of weather ups and downs

Monday, March 5, 2012

With extreme precipitation conditions covering both ends of the spectrum, and conditions varying by region, last year meant a delayed but abundant harvest for some, total crop failure for others

by HENRY HENGEVELD

Most Canadian farmers will likely remember 2011 as a year of precipitation extremes. First, a spring that was much too wet, then a mid-summer that was very dry, followed by a wet and warm autumn. For those in the right places and with the right crops, this resulted in a delayed but abundant harvest. For others, it meant total crop failure.

Not surprisingly, since the extreme precipitation conditions covered both ends of the spectrum, average annual precipitation across Canada was only slightly below normal. Four per cent below, to be exact. Environment Canada also reports that it was once again a warm year, with mean temperatures some 1.4 C above the norm. This was well behind the record 3 C departure set last year, but still tied with 1987 as the eighth warmest since 1948. The cooling effect of a strong La Niña was a key factor in the more moderate temperatures.  

For Ontario, average temperatures were also 1.4 C above normal – the sixth warmest year on record – while annual precipitation was 12 per cent above the long-term average.  

However, as most farmers across Canada will testify, these national and regional averages mask the reality of large seasonal variations during the past year, particularly with respect to precipitation, and the impacts that these can have on farm productivity.  

In Ontario, for example, cold weather, heavy rains and lack of drying sunshine during the spring season delayed crop planting significantly. Across southern Ontario, very little corn was seeded before May, in sharp contrast to the early planting of the previous year. Then came the drought!  During the first four weeks of summer, just as the delayed crops were coming into a critical growth stage, a sequence of hot days with scarcely any rain soon dried up the soil moisture.

Thankfully, just in time, the rains returned, but then stayed. September and October were particularly damp, with some regions reporting more than twice the normal amounts of rain for that time of year. By the end of October, much of the soybean and corn crops were still standing on the fields. Fortunately, a warm fall and delayed onset of the first frost still allowed for a good harvest for most farmers.

Farmers in the eastern Prairies had similar problems, although many fared less well than Ontarians. In southern Saskatchewan and Manitoba, for example, heavy spring rains on already waterlogged soils made it virtually impossible to get on the fields during much of the normal planting season. Some farmers still tried late planting, putting their crops in during June.      However, many completely gave up on planting a crop. In fact, estimates are that some 2.75 million hectares of Prairie cropland were left fallow this year at a cost of several billion dollars to the region's economy.

Then – just as in Ontario – the hot, very dry and sunny weather arrived.  For those who managed to get their crops in, the ideal growing, ripening and harvesting conditions for the next three months resulted in a great crop year. Suddenly, the waterlogged soils of spring became a blessing, since the extended drought conditions experienced in the region during mid-summer would otherwise have devastated the crops. Another reminder that yields are not just based on what weather we get, but more importantly on when we get it.

Offsetting the plight of some of the eastern Prairie farmers was a bonanza year for Alberta farmers. Good growing conditions during spring and summer and amazing harvest weather resulted in well above average yields in the region, more than offsetting the losses from the fallow lands in the eastern part. The net result for the entire Prairies: the fourth highest net return ever!

There were, of course, many other interesting weather stories for 2011 to add to Canadian folklore. A number of these were highlighted in Environment Canada's annual release of top weather stories of the year, issued in late December. Here are a few notables:

Floods. During the spring season, parts of Manitoba and Saskatchewan experienced the highest water levels and river flows in modern memory. Those of the Assiniboine River and Lake Winnipeg were estimated to be one-in-330-year and one-in-2000-year events, respectively. Flooding swamped three million hectares of adjacent farmland. More than 7,000 people had to be evacuated, some losing their homes for good.

Forest fires. While 2011 was not a severe forest fire year for most of Canada, it was for the town of Slave Lake, in northern Alberta. Weeks of warm, dry spring weather in the region had left the aspen forests in tinder-dry conditions, waiting for something to happen. In mid-May, it did! Once the smoke had disappeared, one third of the town had been reduced to rubble, resulting in property losses exceeding $700 million (of which $400 million was insured). This was the second worst economic loss ever for a single natural disaster in Canada, only exceeded by the infamous ice storm in Eastern Canada in 1998.

Then, to complicate matters, the rains started. During June, the Slave lake region received a record-setting 200 millimetres of rainfall. That was followed by another major downpour in July.  Much of what didn't go up in smoke got flooded.  

Extreme summer storms. While 2011 was, in general, relatively uneventful in terms of severe summer storms in Canada, there were several notable exceptions.  One was the F3-category tornado that stuck Goderich on Aug. 21.  Insured property losses exceeded $100 million. There was also one fatality.  

Hurricanes. Although remnants of several major North Atlantic hurricanes brought heavy rains and high seas to parts of Eastern Canada through the year, Hurricane Maria was the only one to make landfall in Canada as a hurricane. While flood and wind damages caused by Maria as she swept across Newfound-land's Avalon Peninsula were moderate, the event was significant in that it was only the 13th hurricane to make landfall in Newfoundland since 1851.

Arctic sea ice. The American National Snow and Ice Data Centre in Colorado reported that September sea ice covering the Arctic Ocean declined to its second-lowest extent on record in 2011.  Arctic ice cover has declined by 12 per cent per decade since 1979.  Furthermore, the ice is getting progressively thinner. While the net volume of the Arctic ice is more difficult to measure than its area, experts estimate net volume for September 2011 to be about 4,200 cubic kilometres, a new record low some eight per cent less than the previous record set in 2010.  How long now before we see an ice-free Arctic Ocean in summer?

The global climate. In early January, the World Meteorological Organization also issued a lengthy report on preliminary results for 2011 global climate statistics. It notes that, despite the cooling effects of a strong La Niña, average global surface temperatures for the year were 0.41 C above normal, thus tying 2010 as the 10th warmest on record. It also notes that this was the warmest year of the record to take place during a La Niña event. The 13 warmest years of the record have now all occurred during the past 15 years.

The damage toll. During 2011, the global community was spared some of the high damages caused by hurricanes during other recent years. However, floods, droughts, heat waves and tornados made up the difference. Munich Re, one of the major players in the global re-insurance industry, noted in its annual disaster report that natural disasters in 2011 claimed the lives of 27,000 people (not including those that perished in the drought-ravaged regions of north-east Africa) and caused property losses in excess of $US380 billion, of which some $US105 billion was insured. This staggering amount far exceeds the previous record of $US220 billion set in 2005.  

Two key events – the February earthquake that devastated the Christchurch region of New Zealand and the awesome seaquake-induced tsunami in March that demolished much of the infrastructure in the region of Tohoku, Japan – dominated these losses. Together, they destroyed $US226 billion in property.

However, the remaining $US150 billion in weather-related disasters still amounted to the second highest loss on record. While, unusually, most of these losses occurred in Asia, a rash of severe tornadoes in the United States made up a whopping $US46 billion of these losses.
Don't be surprised if our property insurance premiums rise next year! BF

Henry Hengeveld is a retired climatologist.