Snow leads to disruption on West Yorkshire's major roads - including M62
Dozens of schools have closed too
There's long queues reported on some of West Yorkshire's major roads amid an amber weather warning for heavy snow.
National Highways warned of delays on the M62 around Junction 23 for Huddersfield, while dozens of schools closed early across Bradford, Kirklees and Wakefield.
Bradford Council confirmed it would be sending gritters out overnight.
The Met Office said up to 25 centimetres of snow could fall across the Pennines between Thursday and Friday (February 08-09).
There is a risk of power cuts, travel delays and some rural communities becoming cut off, the forecaster said.
The snow will ease later in the day, and may turn back to rain or drizzle, especially in the south and east.
There is uncertainty with respect to the rain-snow boundary, and the northern limit of the snow, the Met Office said.
Met Office deputy chief meteorologist Chris Almond said: "While the early part of this week will see some rain, at times heavy, gradually sinking southwards, there's an increased signal for wintry hazards as we move through the week as cold air from the north moves over the UK.
"It's from Thursday that the snow risk becomes more potentially impactful, as mild air attempts to move back in from the south, bumping into the cold air and increasing the chance of snow developing on the leading edge.
"While there are still lots of details to work out, the initial snow risk looks highest in northern England and Wales from Thursday."
The snow will turn into sleet and rain towards the end of the warning period from the south.
Further warnings for ice could also be issued later in the week as temperatures drop below average for this time of year, the forecaster said.