Beginning at noon on Thursday, Metrobus will only operate on major roads in response to hazardous conditions, icy roads, and snow in the region. Metro says riders can expect long delays and wait times, and more bus routes may be suspended if the weather gets worse.

“Buses throughout the region are encountering hazardous conditions, including icy roads and limited visibility during heavy snowfall,” Metro wrote in a press release announcing the changes. “It may be necessary to suspend some routes earlier, if roads become too dangerous for travel.”

Under the “severe snow service plan,” only 58 routes will be in service—compared to its moderate snow service plan, under which 110 routes continue to operate—and some of them will detour to avoid certain roads. Cancellations and routes can be found at Metro’s website.

Some of the already-suspended routes include the 25B, J2, 1A, NH1, NH2, 23A, F1, W2, W3, A6, and D14. Shuttle bus service between Pentagon and Arlington Cemetery will also be suspended, but the shuttle bus from Addison Rd. to and from the Capitol Heights station will continue.

MetroAccess will continue operating as normal, but the transit agency says residents using MetroAccess might experience delays because of the weather. Additionally, people might not be able to get door-to-door service if sidewalks and walkways are inaccessible because of snow or ice.

Metro is encouraging residents to avoid travel and take Metrorail as an alternative to the bus wherever possible.

The transit agency says it will try to keep people updated on further changes to service—but that “limited notice may be necessary” if conditions deteriorate quickly.