Eight people have been taken to hospital after two crashes on the Coquihalla Highway between Merritt and Kamloops.
British Columbia Emergency Health Services says the first call came just before noon on Monday, and it received about a dozen 911 calls.
It says two separate crashes involving at least four vehicles occurred about 90 metres apart from one another near the Lac Le Jeune exit.
The agency says the collisions happened during a sudden hail storm.
It says one person was taken to hospital in serious condition via air ambulance, while seven others were taken to hospital in stable condition by ground ambulance.
Drive B.C. says the highway has been cleared, but to expect major delays due to congestion.