Persistent weak layer overview

REQUIREMENTS
Permission	Operation administrator and higher
Connectivity	Online and partial offline

This document describes the purpose and use of persistent weak layers (PWL) in the InfoEx system.

Background

An in depth understanding of the current condition of PWLs is critical for avalanche forecasting. The new InfoEx system aims to provide better tools for submitting relevant observations, keeping track of the condition of PWLs in your local area(s) and efficiently exchanging this information. The following paragraphs provide a brief overview of the PWL functionality of the InfoEx system.

Managing PWLs

In comparison to the old InfoEx, where PWLs were simply referred to by a burial date, the new system requires users to explicitly define PWLs. This allows PWLs to be tracked more easily and offers opportunities for advanced queries. The InfoEx system supports two different types of PWLs.

Operation PWLs

Operation PWLs are defined by an operation and represents locally observed PWLs in the snowpack. This allows PWLs to be tracked more easily and offers opportunities for advanced queries. Operation PWLs are managed by operations, which have full control over the characteristics of these PWLs.

See the following documents about managing Operation PWLs:

• Creating a new operation PWL
• Modifying the baseline information of an existing operation PWL
• Deleting an existing operation PWL

Community PWLs

Community PWLs is a new concept in the InfoEx system. Since PWLs often exhibit significant spatial variability and might be buried on a range of days, individual operations might create their Operation PWLs differently. Community PWLs provide a mechanism for linking operation controlled Operation PWLs that relate to the same PWL in nature. This grouping of Operation PWLs allows for more meaningful queries in the InfoEx. For example, the community PWL functionality will allow users to more efficiently get a comprehensive picture on the assessments of a PWL that covers a large area and effectively visualize the associated observed avalanche activity.

See the following documents about managing Community PWLs:

• Creating a new community PWL
• Modifying the information for an existing community PWL
• Deleting an existing community PWL

NOTE

At this point any user with Submission Moderator permissions can manage Community PWLs. However, once the necessary filtering functionality, the idea is that the CAC would be taking the lead in managing the Community PWLs that they are in the best position to assess large scale patterns. However, operators always has the ability to unlink their Operation PWLs from a specific Community PWLs if they disagree with the grouping.

Tagging observations with Operation PWLs

To highlight relevant observations, The InfoEx system allows users to tag observations of the following types to be tagged with Operation PWLs.

• Avalanche Observations
  Avalanche observations can be tagged with a single Operation PWL under the failure plane section of the observation entry form to indicate the failure plane of the avalanche.
• Snowpack Observations
  Snowpack observations can be tagged with multiple Operation PWL under the observation details section of the observation entry form to indicate which PWL have been observed in the reported observation.

Assessing Operation PWLs

The new InfoEx system allows users to track the condition of Operation PWLs and how they related to the current avalanche problems. The following workflow modules include PWL functionality:

• Snowpack module
  The snowpack workflow module allows users to keep track of the current conditions of their Operation PWLs in their region(s). Click here for more information on the functionality of this workflow module.
• Hazard assessment module
  The hazard assessment module allows users to identify and characterize the present avalanche problems and associate them with an Operation PWL is necessary. Click here for more information on the functionality of this workflow module.

Filtering InfoEx report by Community PWLs

NOTE	The avalanche problem/PWL filtering functionality for taking taking full advantage of PWL information the InfoEx report has not been implemented yet!

Related documents

• Persistent weak layer overview

Operation PWLs

• Creating a new operation PWL
• Modifying the baseline information of an existing operation PWL
• Deleting an existing operation PWL

Community PWLs

• Creating a new community PWL
• Modifying the information for an existing community PWL
• Deleting an existing community PWL

Assessing PWLs

• Snowpack module

Functionality tested

• n/a