Officials sound alarm over major flood threat
Flooding expected this weekend could be worst Kelowna has ever seen
Widespread flooding — perhaps the worst on record — is expected along Kelowna creeks Friday and Saturday, civic and emergency officials warn.
A combination of warm temperatures, heavy rain and rapid snowmelt could cause Mission Creek and Mill Creek to burst their banks in many locations, resulting in a one-in-200-year flood, officials say.
“We have an unprecedented amount of water coming our way,” Mayor Colin Basran said Wednesday. “This is going to be a very serious situation in our community.”
Extraordinary measures are being taken to try to avert flooding, including the redeployment of 100 provincial firefighters to sandbagging duty and the hurried elevation of a dike along a 3.5-kilometre section of Mission Creek.
But people living in flood-prone areas were cautioned they are ultimately responsible for protecting their own properties, and they should be taking steps immediately to defend against rising waters.
“We have a very important message — localized flooding in the Kelowna region is imminent,” said Brian Reardon, regional district administrator and head of emergency operations. “We are planning for the worst and hoping for the best.”
Current projections are the expected flooding will be a “much larger event” than was seen last weekend when close to 100 Kelowna residences were evacuated as Mill Creek overflowed.
That flooding has left the ground saturated in many areas and unable to absorb any additional moisture that comes in the form of rain, said Todd Cashin, a city planning manager.
“Our cup is full,” he said. “There’s really nowhere else for the rain to go,” except to pool and flood low-lying areas.
A short distance from where officials held a press conference to publicize the flood risk, crews were already working to raise the height of a dike along the north side of Mill Creek.
The dike averages about 2.5 metres in height, and it was being raised by about 30 centimetres with the dumping of a mixture of clay, loam, sand and gravel from a continuous cycle of trucks.
This is going to be a very serious situation in our community.
Mayor Colin Basran
Dike-reinforcing work was being done between Gordon Drive and Casorso Road, and Casorso Road and KLO Road. The provincial government has already agreed to pay $150,000 for the work.
“We’re hoping to have the dike elevated in the next day or two,” Cashin said.
After a high temperature of 25 C on Wednesday quickened the mountain snowmelt in the Okanagan, heavy rain is forecast to begin late today.
By Friday morning, flows in Mission Creek are expected to hit 137 cubic metres per second — the fastest on record, and above the 105 cubic metres recorded at the height of last weekend’s flooding.
Officials could not estimate how many properties along Mill Creek and Mission Creek might be flooded, urging everyone who lives near the waterways to be prepared by sandbagging their properties. They should also be ready to leave at a moment’s notice if evacuation orders are issued.
Peak flows are expected to last only for a few hours, because much of the snowpack at middle and lower elevations has already melted.
That’s in contrast to the situation that developed in the spring of 1997, the worst flood season in recent times, when a “monstrous snowpack” greatly increased creek flows and the lake level for several weeks, said Shaun Reimer, a Ministry of Environment official.
A week after maximum creek flows, the concern will be the amount of water in Okanagan Lake, said Reimer, whose responsibilities include controlling the outflow of lake water at the Penticton dam.
The dam will be releasing water from Okanagan Lake at a predicted velocity of 68 cubic metres per second, about 10 per cent faster than the structure’s design capacity, Reimer said.
“We’ll be at maximum outflow the next few days,” he said, cautioning the release rate may have to be dialled back if flooding results in the South Okanagan.