Ponoka happens to be just about smack dab in the middle of a corridor in central Alberta known for its wild summer storms.
This season looks like it was one of the busiest ones in many years with residents used to seeing thunderstorm warning after thunderstorm warning issued by Environment Canada. Indeed, conditions were just right this summer that a tornado touched down in the north end of town causing damage to some homes.
Highway 2 from Calgary to the south end of Edmonton tend to have major activity, explained Kirk Torneby, meteorologist with Environment Canada. Generally from mid June to August the corridor can have as many as 300,000 lightning strikes. Indeed, one homeowner in Ponoka County had lightning strike her home, causing several large holes in the roof although she was not hurt.
This year saw 576,000 cloud to ground lightning strikes, higher than 2002 numbers, says Torneby. In fact the number of days of severe weather such as hail storm events is higher than meteorologists are used to seeing with 144 hail events compared to the average of 74.
July was the peak time for these hail and thunderstorm events, explained Torneby. While Ponoka sees its fair share of storm activity, other communities along the corridor deal with similar instances. “Not a lot of these communities along this corridor are technically that different.”
“Hail also has a high frequency in that corridor.”
Most folks will remember the long-lasting hail storm that swept through Ponoka last summer that ended up decimating entire fields of crops.
One of the reasons for the frequent activity is the relatively close proximity of the Rocky Mountains to the prairies. What Torneby calls, “mountain-plains circulation.”
Cold, dry air in the upper atmosphere generally blows to the east and northeast from the mountains while warm, low level moisture in the air on the plains mixes with that wind, causing instability.
That temperature differential, says Torneby, is like the gas pedal to the storm. The moisture becomes too heavy and falls while the warm air rises (called a trigger), causing an updraft; and voila, thunder and lightning are created. This creates an ideal backdrop for avid storm chasers and photographers.
“They (wind, heat and moisture) all contribute to the growth and development of these thunderstorms,” said Torneby.
He added that some communities might see small differences depending on their topography. A community in a river valley may see slightly more activity than another.
There are several ways to detect lightning strikes but Torneby says Environment Canada uses a triangulation tower system to detect the number of strikes and their locations.
This year has seen a few other records. Torneby says this was the wettest summer ever on record for Red Deer beating out long-term climate records from as far back as 1908. One thing most people in this area can rely on is extreme weather during the summer months.