September 23, 2020

May 2020 Summary – A fairly normal May and Spring – The Blob, and looking back to 1895.

A very rainy, but not quite record rainy, month.

  • Vancouver Island Inland Sections Forecast - SPECIAL WEATHER STATEMENT IN EFFECT
    Issued: 12:09 PM PDT Wednesday 23 September 2020

    Forecast Issued 7:26 PM PDT Wednesday 23 September 2020 - Wednesday night: Showers at times heavy with risk of a thunderstorm. Amount 10 to 15 mm. Windy this evening. Low 12. Thursday: Showers with risk of a thunderstorm. Amount 10 to 15 mm. High 16. UV index 1 or low. Thursday night: Cloudy. 60 percent chance of showers early in the evening. Rain beginning in the evening. Amount 15 to 25 mm. Low 11. Friday: Showers. Windy. High 18. Friday night: Rain. Low 10. Saturday: Periods of rain. High 20. Saturday night: Rain. Low 11. Sunday: Rain. High 17. Sunday night: Cloudy with 60 percent chance of showers. Low 12. Monday: Cloudy with 60 percent chance of showers. High 18. Monday night: Cloudy periods. Low 11. Tuesday: A mix of sun and cloud. High 21.

The Alberniweather and Alberni Valley Climate Summary for May 2020


Once again, much like April, May was a fairly average month. No temperature records were set for low or high temperatures and only two modest daily rainfall records were set at the Airport. Neither one came close to an all time.

Rainfall was almost exactly normal in the City compared to the 1971-2000 records at the old Somass River station. However, it was only three quarters of normal at the Airport compared to the 1981-2010 records at Robertson Creek hatchery.

Are springs getting wetter or drier?

This month I updated my gigantic spreadsheet that includes temperature and precipitation (which includes melted snow) data for every major station in the Alberni Valley since the first one on Bainbridge road in Beaver Creek.

I added a new table and subsequent graph that looks at the Meteorological Spring — the months of March, April and May — for every station and every year since 1895. Here’s the resulting graph below.

Spring (March+April+May) totals of precipitation at Alberni Valley weather stations since 1895

A quick scan at the graph seems show that amounts of slowly increased over the past 100 years particularly on the high end of the scale. There were no totals over 600 mm before 1945. There have been several since then. At the same time, the lowest lows look fairly constant.

Upon further inspection, and if we discount the values from my station (rightmost in grey) you might start to see a different trend. I’ve drawn in a smooth line that might be a fit to what I see.

Adding a smoothed line along the top of the values.

Was there a gradual increase in rainfall that has now started to reverse in the 1980s or 1990s? Certainly hard to say without a better look at the data and other trends but we’ll keep watching as the years roll on.

Fun Fact: the Beaver Creek station started recording rainfall data in May of 1894 (so we don’t get a “Spring” value for that year) but didn’t start recording temperature data until February of 1900.

Snowpack at Half of Normal.

The snowpack at May 1 for the Island as a whole was at 78% and fairly even across the various stations.

Most island stations held steady through the month except Jump Creek at the head of Nanaimo Lakes. As of June 1, Jump Creek is at just 9% of normal and other stations have begun to drop quickly.

Average snowpack for the Island on June 1 is just 52% of normal.

The Blob Went Deep

The article above from the excellent Hakai Magazine details a study done on the 2013 “Blob” phenomenon in the North East Pacific and its impact on the waters of the fjords of the Central Coast of BC.

Turns out, the Blob didn’t disappear, it sank, and it likely warmed the inlets:

“For those who have braved swimming in British Columbia’s spectacular, glacier-fed fjords, “warm” is probably not a word that springs to mind. But at least four of British Columbia’s fjords are real hotspots for climate change. Since the 1950s, they’ve warmed up to six times faster than the rest of the ocean, according to new data….. The mass of warm water dropped more than a hundred meters below the surface. At depth, the warmth of the Blob lingered until at least March 2018. And that deep, warm water has seeped into the fjords.”

Could this deep, lingering, warm water be impacting salmon runs? Is that contributing to the collapse of this year’s sockeye fishery in the Alberni Inlet? We know salmon don’t do well as water warms… no doubt researchers are investigating the possible correlations.

Story of the Month

The COVID-19 Pandemic marched on

That’s it for this month’s summary! Details and records below!


Daily and All Time Records Set

Set at the Airport* since 1994 and compared to other stations** for “All Time” since 1900.


Just two daily high precipitation records were set at the Airpot but neither approached all time highs for the day. No high or low temperature records were set.

  • May 12 high precip 18.3 mm: #1 is 33.9 mm at Robertson Creek in 1986
  • May 16 high precip 15.7 mm: #1 is 49.3 mm at Beaver Creek in 1941.

City Station Comparisons

Mean Min, Mean, and Mean Max Temperature, 
Total Precipitation and Highest Wind


  • Alberniweather: 8.7 ºC, 13.7 ºC, 19.2 ºC62.0 mm , S 49.9 kph on 2nd
  • Alberni Elem. : 8.5 ºC, 13.5 ºC, 18.9 ºC, 84.8 mm, SE 35 kph on 11th
  • Maquinna Elem.: 8.6 ºC, 13.4 ºC, 18.8 ºC, 80.5 mm, – 34 kph on 2nd
  • Neptune: 8.7 ºC, 13.6 ºC, 19.7 ºCNA*** , S 9 kph on 30th
  • Nick’s (Maq area): 8.4 ºC, 13.2 ºC, 18.3 ºC62.4 mm, ESE 44.4 kph on 2nd

City and Airport
Compared to Normal


Differences from Normal (1971-2000) in the City

+3.0° C, +1.8º C, +1.3 ºC-3.2 mm (95%)

This Month’s Average City Values

Differences from Normal (1981-2010) at the Airport

+1.0° C, +0.7º C, +0.4º C -18.0 mm (79%)

This Month’s Average Airport Values

Official Days of Precipitation at Airport*

Normal DaysDays This Month
>= 0.2 mm: 14.6 :  15
>= 5 mm:  4.8 : 4
>= 10 mm: 2.3 : 3
>= 25 mm: 0.3 : 0


* May have used backup Environment Canada Data source at WeatherStats.ca or Missing Data (January 2020)

**^^ Missing Data from Airport, Alberniweather broke existing Airport record temperature. Temperature at Alberniweather will be different. Usually Alberniweather underestimates temperatures in summer compared to Airport.

** Short Term means since 1995 at the new AVRA Airport.  Airport Records are compared to the 30+ year weather stations of record since 1900 (1895 for rain) at Beaver Creek, Port Alberni "City" and Robertson Creek.  Note that records pre 1950 may be more likely to over-estimate high temperatures.

***Rain gauge faulty. ****Alberni Elementary station offline.

****Nick's data currently unavailable (not Nicks fault :)) 

^Estimated amount, as new rain gauge installed on the 7th, used Alberni Elementary totals before that date.

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