Last month went down in the record books as the hottest April in Chilliwack since records began.
“Re-occurring upper level high pressure ridges, resembling a summer time weather pattern, produced a total of thirteen high temperature records,” said Roger Pannett, volunteer weather observer for Environment Canada.
“Eleven of those high temperature records occurred soon after mid-month, during an unusual April provincial heat wave which produced over 100 high temperature records in B,C. With mean temperatures at 13.93°C, an amazing 4.43°C above normal, it was the hottest April since records commenced in 1895. The previous hottest April was in 1934 when mean temperatures were at 13.2°C. For the 4th consecutive month and the 3rd consecutive April, temperatures were well in excess of the standard deviation of + or – 1.1°C.”
With that province-wide heat on the heels of a warmer than normal winter driven by a strong El Nino event, there has been a significant and rapid melt of the provincial snowpack. According to the River Forecast Centre, on May l the snowpack ranged from 12 per cent to 100 per cent of normal with a provincial average of 53 per cent of normal snowpack.
However, according to the Centre’s graphs, the Chilliwack River is fairing a little better at 83 per cent of normal while the Skagit watershed is at just 23 per cent of normal and the Lower Fraser overall is at 72 per cent.
The May 1 provincial snowpack average was a decline of 38 per cent from a month ago when, on April 1 the snowpack was 91 per cent. The May l average sets a new record low (measured since 1980) and 13 per cent below the previous all-time low of 66 per cent in 1980. Of the 183 snow survey measurements taken May 1, 33 stations showed new record lows.
Today, low and mid-elevation snow is pretty much all gone for all areas of the province with snow remaining only at high elevations.
The low snow pack ties into the extraordinary lack of rain this year. Pannett said that the precipitation for the first four months of the year in Chilliwack was just 575.6 mm on 72 days compared to the average of 760.8mm on 68 days, representing 75.66 per cent of normal. Rainfall totals for April were over 50 per cent below normal.
All this could add up to low river flows in the critical summer months when salmon are returning to spawning streams.
This trend in heat and dryness isn’t confined to British Columbia. The Prairie Climate Centre forecasts that, if business continues as usual, southern Manitoba could see sustained temperatures similar to parts of Texas in the future.
The prairies are likened to the canary in the coalmine in that they are already known for extremes of heat and cold. However, they are warming faster than the global average and, by 2050, Winnipeg could be experiencing close to 50 days of over 30oC temperatures, four times the current average of 11 days. This will profoundly change how people live, work and grow food on the prairies. Food and livestock feed production may be extended further north and the growing season may be longer.
For this year, though, the Climate Prediction Center at the U.S. National Weather Service/NOAA is expecting El Nino conditions to neutralize by early summer with a potential for its cold counterpart, La Nina, to ramp up in the fall
In the meantime, according to Pannett, Chilliwack’s historical precipitation records show that a dry April often precedes a hot, dry summer. That could lead to drought conditions like last year during the peak of the growing season.
It looks like this is the new normal.