In a message to staff, seen by The Independent, the ambulance service said it had made the decision at 1pm today because of both the worsening weather conditions and high levels of 999 calls.
It said: “Heavy snow is currently affecting north, west and south Yorkshire and having a severe impact on our operations.
“We are implementing a number of actions in order to protect our core services for patients and respond to the ongoing demand, including increasing our 4×4 capacity, implementing mutual aid arrangements and identifying staff who would be available at work at short notice.”
The message urged staff to prepare for the weather and to make sure they left enough time to get to work.
It said: “We have a duty of care to our patients to continue to provide safe and responsive services. They will be relying on us to be there for them so we urge you to build some resilience into your own travel-to-work plans.”
Hundreds of schools across the region and an NHS vaccination centre at the Priory Campus in Yorkshire have also been closed.
Coronavirus testing centres in Kirklees and Bradford have also closed.
Mark Millins, strategic commander at the trust, said: “Due to the very snowy conditions across West, South and North Yorkshire, driving conditions are very difficult and many roads are gridlocked so this is having a severe impact on our operations.
“We are asking members of the public to only call us in a serious or life-threatening emergency to help us focus our efforts on our most poorly patients. Our dedicated staff are working extremely hard to reach patients as quickly and safely as possible but, understandably, the hazardous driving conditions and blocked roads mean that it is taking us longer than normal in the worst-hit areas.
“Please take extra care when out driving or walking and, where possible, avoid travelling at all in snowy or icy conditions. If you do have to go out, ensure that you wear appropriate footwear and warm clothing. Also, please stay in touch with elderly and vulnerable relatives and neighbours to ensure they are safe and well.”
