Winter Weather Advisory: What Southern California Drivers and Mountain Visitors Need to Know as Snow Piles Up

A Winter Weather Advisory now matters most to people driving into the mountains and anyone planning a short trip to snowy areas: travel is already constrained, and the next few hours and nights will determine whether a planned outing becomes an extended roadside wait. Chain rules, icy roads and pockets of deep snow are creating immediate friction for drivers and local communities, particularly around the San Bernardino range and the broader Sierra Nevada travel corridor.

• Expect chain controls on most mountain roads; enforcement has already turned some visitors away.
• Snow depths in parts of the San Bernardino Mountains have reached up to three feet in recent days.
• Clearing skies are increasing the risk of black ice overnight; slow speeds and extra supplies are recommended.
• Those unfamiliar with chain installation are facing real delays and safety hazards when attempting to drive up without equipment or experience.

Winter Weather Advisory — immediate precautions for drivers and visitors

Here’s the part that matters: if you plan to go up to mountain communities, treat the trip like an expedition rather than a short drive. All mountain roads are under a level 2 chain requirement, which means chains or traction devices are mandatory for most vehicles. Exemptions are limited to vehicles described as having four-wheel drive or all-week drive paired with four snow-tread tires, but those vehicles are still required to carry chains in case conditions worsen.

If you’re wondering why this keeps coming up: several recent storms have dumped substantial snow in localized mountain ranges, and while skies are clearing, colder overnight temperatures are creating black-ice risk on routes that look deceptively dry in daylight. Driving at very low speeds is being recommended; one practical guideline being emphasized is maintaining 25 mph on icy stretches.

What to pack before you leave: extra water, food and blankets. These are simple items that change an inconvenient delay into a manageable one if you get sidelined by chains, traffic holds or a turnback by officers enforcing requirements.

Snow totals, road rules and travel conditions

Travel troubles are stretching across the Sierra Nevada corridor and into Southern California mountain ranges. In the San Bernardino Mountains, up to three feet of snow fell over the past few days, creating deep patches and icy approaches to mountain communities. Law enforcement officers have been stopping drivers who attempt to head up without chains; some motorists have been turned away at checkpoints, while others have had to learn chain installation on the roadside.

Clearing skies have a double edge: they end active snowfall but drop temperatures overnight, which increases black-ice potential on previously wet roads. The guidance from officials has been practical—slow speeds, carry traction equipment, expect enforcement and bring basic survival supplies if you plan to be on mountain roads.

• Level 2 chain requirement: chains or traction devices required for most cars.
• Exemptions: vehicles with four-wheel drive or all-week drive with four snow-tread tires (must still carry chains).
• Recommended speed in icy conditions: around 25 mph.
• Essential kit: water, food, blankets, traction devices and patience.

Mini timeline of recent conditions:

• Past few days: repeated storms produced heavy snowfall in the San Bernardino Mountains, with localized accumulations up to three feet.
• Immediate present: skies clearing but colder overnight lows creating black-ice risk.
• Near-term outlook: chain requirements remain in force and enforcement is active on key access roads.

What’s easy to miss is how quickly a cleared sky can worsen driving conditions at night; a dry afternoon can become an icy early morning. The real test will be whether drivers adjust plans and gear up before heading into affected zones.

Short practical Q& A:

• Q: Do I need chains? A: Expect to need them—most mountain roads are under a level 2 chain requirement.
• Q: Can I drive up without experience? A: Drivers who have never fitted chains are already encountering delays; consider practicing or getting help before you go.
• Q: If I’m turned away, what then? A: Stay prepared with supplies and plan alternate, lower-elevation activities or postponements.

For people planning trips, consider postponing nonessential travel into the mountains until conditions stabilize and chain requirements are lifted. For local operators and emergency planners, these conditions will continue to demand active enforcement and visitor education while snowpack remains deep in targeted areas.