The Northern Tornadoes Project (NTP) has wrapped up its investigation into four storms on May 18, including one in Mattawa.
Officials confirm a downburst at 8 pm that day with winds up to 115 km/h.
They say tree damage was reported in and north of Mattawa along with one injury.
A ground and drone survey was also completed a few days after the storm, documenting the reported damage along with minor damage to a warehouse building.
Officials say there was damage over an area at least 8 km long and up to 6 km wide.
You can find the NTP report on its website.
