A downpour of spring rainfall records
‘It’s clobbering the previous records’
More than a foot of rain in the past two months has washed away all kinds of weather records in Ottawa.
Wettest May. Wettest April and May combined. Wettest spring. (The weather office defines spring as March 1 through May 31.) Rainiest first five months of the year.
And most of these are records not by a millimetre, but by huge margins.
May (measured through Tuesday) had a record of 175 mm of rain at the Ottawa International Airport, more than double the average of 86. Records there go back to 1939.
“If it was just May, then nobody would feel sorry for you,” said David Phillips, senior climatologist at Environment Canada. But there’s much more:
April brought 147 millimetres of rain, another record. The norm is 63. “So that’s way more than double.”
Two record months back-toback combine into one monster record. Together, April and May brought 323 mm (12.7 inches) of rain, and it’s this combined figure that caused our flooding, along with the melting of a deep snowpack. The rain is 180 mm more than normal. In effect, we got more than four average months’ worth of rain in 60 days (since May 31 hasn’t been totalled yet).
“That’s more than 70 millimetres more than the previous wettest April-May,” Phillips said — in effect, beating the previous record by a margin of one month’s normal rainfall.
“It’s clobbering the previous records. It’s like a different regime. I often get excited by a tenth of a degree or a one-millimetre record. But this is not even close.”
It’s also the most rain for March through May, which the weather office calls spring because it saves calculating fractions of a month. The 374 millimetres beats the previous by 62 millimetres.
And it’s the wettest first five months of a year, this time by a margin of 80 millimetres.
“It has rained often and it rained hard,” Phillips said.
In May, we had 19 days of rain and three more with traces too small to measure accurately.
We have had six days this year with more than 25 millimetres of rain. The norm is one day.
And it was cool — not record cold, but a bit gloomy with an average high of only 17.2 C. A couple of days above 30 C skew that average higher. Really it was cooler than that for most of the month.
Canadians are funny about bad weather, Phillips noted: “People will cheer ugly weather just to break records.” Several years ago, when Ottawa fell one centimetre short of record snowfall for the year, “people were robbed of their conversation piece. But not this year.”
The forecast for early June, meanwhile, “is not good.” More rain.