Flags/Lemons

In 2005 Bruce Jamieson and Jürg Schweizer in their paper titled "Using A Checklist To Assess Manual Snow Profiles" identified three layer properties and three interface properties that would be tested against critical ranges and would be used to “flag” instabilities in the snow profile. This was implemented in Snowpro Plus+.

Figure 1 - Flags Showing Unstable Interfaces

Figure 1 shows a sample of a profile showing the flags with 3 interfaces highlighted in red indicating possible instabilities. The interface criteria can be user configured as shown in the Preferences/Layer Flags dialog in Figure 5. 

Figure 2 - Flags Setup Dialog

This tool makes it very easy for novices to recognize the unstable layers. However, as noted by Jamieson and Schweizer, “its value in making decisions about avalanche risk is unclear, especially for experienced avalanche practitioners.”