The event in Nyahururu is a hail storm. Such storms occurs when there is abrupt convection and rain clouds form too fast.
— Kenya Met Department (@KenyaMetService) July 4, 2017
This is not the first time the Met. Department has dismissed reports of snow in Nyahururu. In 2015, hailstones were experienced in Kinangop, Njabini, and Nyandarua.
The spectacle was also experienced in Nyahururu in 2008.
Now you know!