Alberta Frost Laws, Seasonal Load Weight and Speed Restrictions – 2026

"Winter season weights for heavy haul and Period 4 season weights for service rigs remain in effect north of the thaw line."

Current Thaw Line Position

The Alberta frost thaw contour map shows a progressive thaw line advancing northward through the 2026 spring season. The following boundary positions are documented on the current map:

• March 5, 2026: Thaw line at Township 28
• March 9, 2026: Thaw line advanced to Township 35
• March 19, 2026: Thaw line advancing to Township 58 spring/Period 1 weights take effect south of and including this boundary at 12:01 am

As of the map's last modification on March 16, 2026, the operative upcoming boundary is Township 58, effective March 19, 2026. Roads south of and including Township 58 will be under spring/Period 1 weight rules. Roads north of Township 58 remain under winter/Period 4 weight rules until the thaw line advances further.

Weight Season by Zone

Specific weight values (axle limits, gross limits) are not published in the frost thaw contour map source. Consult Alberta Transportation or the applicable weight schedule regulation for exact limits under each season designation.

Coverage Scope

• This source covers Alberta provincial highways only. The thaw boundary is defined by township lines as published on the provincial frost thaw contour map.
• Local and municipal roads are not covered by this provincial source. Contact the relevant municipality directly for local road restrictions.
• Road classifications affected: heavy haul routes and service rig routes.

Exemptions and Permits

No exemptions, permit categories, or commodity exceptions are specified in the frost thaw contour map source for the current restriction period. Verify exemption eligibility directly with Alberta Transportation before dispatch.

How to Use This Information for Dispatch

• Determine your route's position relative to Township 58 the thaw line boundary effective 12:01 am March 19, 2026.
• If operating south of or at Township 58: apply spring season weights (heavy haul) or Period 1 season weights (service rigs) as of March 19, 2026.
• If operating north of Township 58: winter season weights (heavy haul) or Period 4 season weights (service rigs) remain in effect until further notice.
• The thaw line advances as temperatures rise. The map has already recorded movements from Township 28 (March 5) to Township 35 (March 9) to Township 58 (March 19). Check the frost thaw contour map PDF for updated boundary positions before each trip during spring thaw season.
• For real-time highway conditions, also consult 511.alberta.ca.