California 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: Bridgeport Avalanche Center Eastside Region Mount Shasta Central Sierra Nevada

Avalanche Report

Pre-populated CalTopo Map

2025-02-22 Avalanche Danger

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• Moderate danger (above 8701')
• Moderate danger (6201' to 8700')
• Moderate danger (below 6200')

2025-02-22 Deep Persistent Slab

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• NW to E aspects (above 8701')
• NW to E aspects (6201' to 8700')
• NW to E aspects (below 6200')

2025-02-22 Wind Slab

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• All aspects (above 8701')
• NW to SE aspects (6201' to 8700')

Issued at: Friday, February 21, 2025 7:00AM
Issued by: BAC

Avalanche Report

Pre-populated CalTopo Map

2025-02-22 Avalanche Danger

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• Moderate danger (above 10001')
• Moderate danger (7801' to 10000')
• Moderate danger (below 7800')

2025-02-22 Persistent Slab

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• NW to E aspects (above 10001')
• NW to E aspects (7801' to 10000')
• NW to E aspects (below 7800')

2025-02-22 Wet Loose

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• E to W aspects (7801' to 10000')
• E to W aspects (below 7800')

Issued at: Friday, February 21, 2025 7:00AM
Issued by: ESAC

Avalanche Report

Pre-populated CalTopo Map

2025-02-22 Avalanche Danger

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• Low danger (above 8701')
• Low danger (6201' to 8700')
• Low danger (below 6200')

2025-02-23 Wet Loose

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• E to W aspects (6201' to 8700')
• E to W aspects (below 6200')

2025-02-23 Wind Slab

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• NW to S aspects (above 8701')

Issued at: Saturday, February 22, 2025 6:31AM
Issued by: MSAC

Avalanche Report

Pre-populated CalTopo Map

2025-02-22 Avalanche Danger

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• Moderate danger (above 8701')
• Moderate danger (6201' to 8700')
• Moderate danger (below 6200')

2025-02-22 Persistent Slab

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• NW to E aspects (above 8701')
• NW to E aspects (6201' to 8700')
• NW to E aspects (below 6200')

Issued at: Friday, February 21, 2025 7:00AM
Issued by: SAC

Zone

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