Overview

The Canyon Alert system is brought to you by the Unified Police Department. Our goal is to provide a one-stop source of canyon traffic information. By subscribing you can prevent the inconvenience of an unexpected delay in the event of a canyon closure or restrictions.

Subscription Options

With our alert system you can get updates on the current traffic status in Big and Little Cottonwood canyons in real time through a number of subscription methods. Pick the one that best suits your needs.

How to subscribe

  • Twitter: Follow “CanyonAlerts” on twitter.
  • Facebook: “Like” our “CanyonAlerts” Facebook page.

Subject to twitter's and Facebook availability and up time

How to unsubscribe

  • Twitter: From your twitter account Un-Follow “CanyonAlerts” on twitter.
  • Facebook: From your Facebook account “UnLike” our “CanyonAlerts” Facebook page

Canyon Restrictions

Snow Tire, 4x4, Tire Chain Requirements in the Cottonwood Canyons

The Utah Department of Transportation requires ALL vehicles travelling in Big and Little Cottonwood canyons to be equipped with approved snow tires or traction devices when the traction law is in effect, communicated by UDOT via road signage, social media, the UDOT Traffic App and the website.

The traction law is specific to a few critical parts of the highway and is only used during severe winter weather. Requiring traction devices during severe weather events at specific locations prevent the roadway from being blocked by vehicles unable to negotiate the road, improving mobility.

The traction law also reduces the number of vehicles departing the roadway, which improves safety. The traction law’s reduction in blockage and run-off the road incidents provide an alternative to closing the road (or having the road close itself).

Four Wheel Drive & All Wheel Drive Vehicles

Approved tires for Four Wheel Drive and All-Wheel Drive vehicles can be identified by an M+S or M/S (mud and snow) or a Snowflake symbol on the sidewall of the tire. These tires must be must be mounted on all four tires of the vehicle. Utah Code 41-6a-1636 requires tires to be in a safe condition. Tires without sufficient tread depth will not be effective. No bald tires! Traction devices such as chains, snow socks, tire studs are also acceptable. When the traction law is in effect, you must be equipped with traction devices or the appropriate snow tires before traveling in the Cottonwood Canyons (S.R. 210 and S.R. 190).

Two Wheel Drive Vehicles

The traction device requirement for two wheel drive vehicles (under 12,000 GVW) when the traction law is in effect is to have four 3 peak mountain snowflake tires (3PMSF). Traction devices such as chains, snow socks, tire studs are also acceptable. When the traction law is in effect, you must be equipped with traction devices or the appropriate snow tires before traveling in the Cottonwood Canyons (S.R. 210 and S.R. 190).

Two wheel drive vehicles MAY be denied canyon access if law enforcement believes they present a hazard to safe travel and other motorists. As a general rule vehicles equipped with aggressive snow tires will be granted access but there may be times, due to very poor road conditions or deep snow, when they are denied access. The police officer will need to make this determination based on common sense and known road condition information.

Our goal is to provide the safest driving experience possible while travelling the canyons. One improperly equipped vehicle can put many other people at risk. Please email our canyon officers at with any additional questions about road restrictions or canyon closures. help@canyonalerts.org

Two wheel drive vehicles with four mounted snow tires (without studs) MAY be denied canyon access if law enforcement believes they present a hazard to safe travel and other motorists. As a general rule vehicles equipped with aggressive snow tires will be granted access but there may be times, due to very poor road conditions or deep snow, when they are denied access. The police officer will need to make this determination base on common sense and known road condition information.

Our goal is to provide the safest driving experience possible while travelling the canyons. One improperly equipped vehicle can put many other people at risk. Please email our canyon officers at with any additional question about road restrictions or canyon closures. help@canyonalerts.org

UDOT Snow Tire and Chain Up Requirements

Other information about UDOT’s Traction Law

Why did UDOT change from M+S to 3PMSF tire requirements?

Requiring 3PMSF tires gives UDOT the option to keep a road open that would otherwise be closed to all because it is impassable by vehicles with all-season tires. M+S tread is a feature of all-season tires, and most vehicles on the road have all-season tires. As a result, M+S tires no longer signify vehicles with more traction than the typical vehicle.

Because everyone has M+S tires, UDOT no longer requires traction devices in conditions that can be negotiated with M+S tires.

What is the difference between 3PMSF and M+S and M/S tires?

M+S and M/S tires are the same thing. Tire tread pattern is the only requirement for an M+S or M/S rating, while 3PMSF tires are required to meet performance standards on a snow-packed track that indicate improved traction and control in winter conditions. This is accomplished by a different rubber compound that provides more grip on snow and on cold pavement than an all-season tire.

What do I do if I don’t have 3PMSF Tires?

Only 5% of state routes are Class II chain segments, and there is no requirement for 3PMSF tires on the remaining 95% of UDOT roads. On the Class II chain segments, traction devices are required only when the road cannot be negotiated with all-season tires. In those cases, you have two other options besides 3PMSF

  • Use tire chains or other traction devices - a set of chains costs around 30 dollars.
  • Wait until the storm clears - UDOT works as fast as we can to clear the road and lift the restriction.

For more information on the traction law visit:
Utah Office of Administrative Rules

Traction Law Card

Canyon Alerts

Partners