When searching an avalanche for a transmitting beacon (i.e., the "signal search"), the distance between your zigzagging paths is called the "search strip width." A wide search strip allows you to cover a large debris field more quickly, but you risk reaching the bottom of the avalanche without receiving a signal. A narrow search strip ensures that you'll receive a signal, but it will take longer to search the entire debris field.
IKAR is an international organization that provides recommendations for mountain rescue know-how. They recommend that transceiver manufactures publish a recommended search strip width that is "about equal to 1.4 (± 0.1) times the realistic maximum range..." That distance is intended to allow for sufficient overlap between search strips.
The following table shows the average ranges that were measured during my range tests, the calculated search strip width (i.e., the measured range multiplied by 1.4), and the manufacture's recommended search strip width. You can see that all of the manufacture's search strip widths are well within the calculated values (although the Zoom+'s recommended width is very close to its calculated width and the Tracker DTS is fairly close).
| Search Strip Widths | |||
| Measured | Search Strip | ||
| Transceiver | Range | Calculated | Published |
| Tracker DTS | 34 | 48 | 40 |
| Ortovox Zoom+ | 31 | 43 | 40 |
| Ortovox 3+ | 36 | 50 | 40 |
| Tracker (T2/T3) | 42 | 59 | 50 |
| Pieps DSP (ave.) | 45 | 63 | 50 |
| Mammut Pulse | 54 | 76 | 50 |
| Ortovox S1 | 50 | 70 | 50 |
Alternatively, the most recent recommendation from the American Institute for Avalanche Research and Education (AIARE) is 30 meters without reference to any particular combination of beacons. This is shorter than even the shortest of all of the published search strip widths for any current beacons, but it accounts for perpendicular alignment, older digital beacons with shorter search ranges, and our inability to accurately estimate distances. I think 30 meters (100 feet) is an appropriate distance (and even shorter for Tracker transceivers).
These two drills will improve your search strip width knowhow. You'll first want to decide what search strip width you plan to use. If you're unsure, choose 30 meters.
When in doubt, make narrower search strips. The minute or two you lose making narrower strips won't kill your friend; having to search the avalanche again, might.
