Northern Ireland snow: Rare 'snow rollers' spotted in County Down

The snow rollers were photographed by entomologist Adam Mantell in Annahilt

It might look like someone has been out having fun in the snow, but the rare snow rollers spotted in a field in County Down are a naturally occurring phenomenon.

They occur when strong winds blow across a flat, snow-covered field or hillside, according to the Royal Meteorological society (RMETS).

The photos were taken in Annahilt by entomologist Adam Mantell.

It came after Northern Ireland was hit with heavy snow on Thursday.

According to Royal Meteorological Society (RMETS) three conditions need to be met for the snow rollers to form:

• The ground must be icy or covered with a snow crust

• Winds must be strong and gusty

• Snowfall must be wet and at least a couple of inches deep

The snow rollers usually resemble hay bales, doughnuts or a swiss roll.

RMETS say snow rollers cannot form if the wind is too strong, too weak or the snow is too tightly packed.

The snow rollers often look like a hay bale, a doughnut or a Swiss roll, and can be hollow inside.

The heavy snowfall caused major disruption across Northern Ireland, with many schools closed and power outages in homes.