Montana Avalanche Danger Report Interactive Map

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"Where's the danger?" Here are autogenerated DEM Shading rules for each advisory zone that allow for quickly adding avalanche danger and problem layers to CalTopo maps.

Show Instructions

Digital Elevation Model (DEM) shading let's you create custom shading schemes based on elevation, slope, aspect and tree cover.

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Avalanche Report

The selected elevation bands are not meant to be exact, but represent a characteristic of the terrain which varies locally.

The highest band, ATL (Above Tree Line), typically includes alpine areas beginning as the treeline transitions into open slopes extending to ridges and peaks.

The middle band, NTL (Near Tree Line), is typically a narrow transition zone between dense forests and treeless alpine areas.

The lowest band, BTL (Below Tree Line), typically extends from valley floors or snowline to near treeline.

Adjusting bands

The default elevation bands may not be accurate for the current zone, you can adjust the bands by dragging the sliders.

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Usage

You'll find that Terrain Modeling in the left pane will show layers that can be turned on and edited. The right pane will show Custom Layers that can be toggled on or off.

Select A Zone: Flathead Range & Glacier NP Swan Range Whitefish Range Bridger Range Cooke City Island Park Lionhead Area Northern Gallatin Range Northern Madison Range Southern Gallatin Range Southern Madison Range East Cabinet Mountains Purcell Mountains Bitterroot Rattlesnake Seeley Lake

Avalanche Report

Pre-populated CalTopo Map

2025-12-20 Avalanche Danger

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• Moderate danger (above 6101')
• Low danger (4401' to 6100')
• Low danger (below 4400')

2025-12-20 Wind Slab

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• NW to SE aspects (above 6101')
• NW to SE aspects (4401' to 6100')

Issued at: Friday, December 19, 2025 6:59AM
Issued by: FAC

Avalanche Report

Pre-populated CalTopo Map

2025-12-20 Avalanche Danger

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• Moderate danger (above 6101')
• Low danger (4401' to 6100')
• Low danger (below 4400')

2025-12-20 Wind Slab

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• NW to SE aspects (above 6101')
• NW to SE aspects (4401' to 6100')

Issued at: Friday, December 19, 2025 6:59AM
Issued by: FAC

Avalanche Report

Pre-populated CalTopo Map

2025-12-20 Avalanche Danger

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• Moderate danger (above 6101')
• Low danger (4401' to 6100')
• Low danger (below 4400')

2025-12-20 Wind Slab

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• NW to SE aspects (above 6101')
• NW to SE aspects (4401' to 6100')

Issued at: Friday, December 19, 2025 6:59AM
Issued by: FAC

Avalanche Report

Pre-populated CalTopo Map

2025-12-20 Avalanche Danger

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• Considerable danger (above 6101')
• Moderate danger (4401' to 6100')
• Low danger (below 4400')

2025-12-20 Persistent Slab

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• All aspects (above 6101')
• W to E aspects (4401' to 6100')

2025-12-20 Wind Slab

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• All aspects (above 6101')
• All aspects (4401' to 6100')

Issued at: Friday, December 19, 2025 7:08AM
Issued by: GNFAC

Avalanche Report

Pre-populated CalTopo Map

2025-12-20 Avalanche Danger

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• High danger (above 6101')
• High danger (4401' to 6100')
• High danger (below 4400')

Issued at: Friday, December 19, 2025 6:20PM
Issued by: GNFAC

Avalanche Report

Pre-populated CalTopo Map

2025-12-20 Avalanche Danger

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• Considerable danger (above 6101')
• Considerable danger (4401' to 6100')
• Moderate danger (below 4400')

2025-12-20 Persistent Slab

Copy to clipboard

• All aspects (above 6101')
• All aspects (4401' to 6100')

2025-12-20 Wind Slab

Copy to clipboard

• All aspects (above 6101')
• All aspects (4401' to 6100')
• All aspects (below 4400')

Issued at: Friday, December 19, 2025 7:08AM
Issued by: GNFAC

Avalanche Report

Pre-populated CalTopo Map

2025-12-20 Avalanche Danger

Copy to clipboard

• Considerable danger (above 6101')
• Considerable danger (4401' to 6100')
• Moderate danger (below 4400')

2025-12-20 Persistent Slab

Copy to clipboard

• All aspects (above 6101')
• All aspects (4401' to 6100')

2025-12-20 Wind Slab

Copy to clipboard

• All aspects (above 6101')
• All aspects (4401' to 6100')
• All aspects (below 4400')

Issued at: Friday, December 19, 2025 7:08AM
Issued by: GNFAC

Avalanche Report

Pre-populated CalTopo Map

2025-12-20 Avalanche Danger

Copy to clipboard

• Considerable danger (above 6101')
• Considerable danger (4401' to 6100')
• Moderate danger (below 4400')

2025-12-20 Persistent Slab

Copy to clipboard

• All aspects (above 6101')
• All aspects (4401' to 6100')

2025-12-20 Wind Slab

Copy to clipboard

• All aspects (above 6101')
• All aspects (4401' to 6100')
• All aspects (below 4400')

Issued at: Friday, December 19, 2025 7:08AM
Issued by: GNFAC

Avalanche Report

Pre-populated CalTopo Map

2025-12-20 Avalanche Danger

Copy to clipboard

• Considerable danger (above 6101')
• Considerable danger (4401' to 6100')
• Moderate danger (below 4400')

2025-12-20 Persistent Slab

Copy to clipboard

• All aspects (above 6101')
• All aspects (4401' to 6100')

2025-12-20 Wind Slab

Copy to clipboard

• All aspects (above 6101')
• All aspects (4401' to 6100')
• All aspects (below 4400')

Issued at: Friday, December 19, 2025 7:08AM
Issued by: GNFAC

Avalanche Report

Pre-populated CalTopo Map

2025-12-20 Avalanche Danger

Copy to clipboard

• Considerable danger (above 6101')
• Considerable danger (4401' to 6100')
• Moderate danger (below 4400')

2025-12-20 Persistent Slab

Copy to clipboard

• All aspects (above 6101')
• All aspects (4401' to 6100')

2025-12-20 Wind Slab

Copy to clipboard

• All aspects (above 6101')
• All aspects (4401' to 6100')
• All aspects (below 4400')

Issued at: Friday, December 19, 2025 7:08AM
Issued by: GNFAC

Avalanche Report

Pre-populated CalTopo Map

2025-12-20 Avalanche Danger

Copy to clipboard

• Considerable danger (above 6101')
• Considerable danger (4401' to 6100')
• Moderate danger (below 4400')

2025-12-20 Persistent Slab

Copy to clipboard

• All aspects (above 6101')
• All aspects (4401' to 6100')

2025-12-20 Wind Slab

Copy to clipboard

• All aspects (above 6101')
• All aspects (4401' to 6100')
• All aspects (below 4400')

Issued at: Friday, December 19, 2025 7:08AM
Issued by: GNFAC

Avalanche Report

Report not available. See IPAC for more information.

Avalanche Report

Report not available. See IPAC for more information.

Avalanche Report

Report not available. See WCMAC for more information.

Avalanche Report

Report not available. See WCMAC for more information.

Avalanche Report

Report not available. See WCMAC for more information.

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