According to DIG (Kumaon Range) PS Sailal, the squall hit the region on the intervening night of April 30 and May 1.
A watchman died in a wall collapse triggered by the squall in the Rudrapur area of Udham Singh Nagar district, he said.
A girl was killed in the Kichcha area when she was hit by a tin roof which was torn off by strong winds.
A five-year-old girl was killed in a wall collapse in the Dhari area of Nainital district, the DIG said, adding that 10 persons were also injured in incidents triggered by the squall.
Meanwhile, officials said that the squall also caused damage to fruit plantations, especially litchi and mango orchards, which they are now trying to assess.