The "signal search" consists of zigzagging the avalanche debris while searching for a signal. The goal of the signal search is to receive a strong signal. If you switch your transceiver to search mode and receive a strong signal, you have already completed the signal search.
If you haven't received a signal, start at the last seen area (LSA, this is sometimes called the "point last seen," or PLS) and move down the avalanche path in a zigzag pattern until you obtain a signal. Starting at the LSA can significantly reduce the size of the search area. However, misjudging the LSA can result in you ending up at the bottom of the avalanche without obtaining a signal. If this happens, you will have to repeat the search—this time while humping back up the mountain. Unfortunately, if the last person skiing down a slope is buried, the rescuers will have to search while hiking uphill. When in doubt, start searching above the LSA.
The distance between your zigzags is referred to as the "search strip width." Each manufacture publishes a recommended search strip. The Neo+, Barryvox and Barryvox S recommend a whopping 70 meters, the Powder/Recon and Pro/Guide recommend 60 meters, the Tracker2, and Tracker3 recommend 50 meters, and the Ortovox 3+ and Zoom+ recommend 40 meters (you can see all of the recommended search strip widths in the avalanche transceiver comparison). These distances are all extremely aggressive! In most cases, leaving no more than 100-feet (30 meters) between each zigzag is conservative, safe, and appropriate. When in doubt, make narrower search strips (i.e., about half the range stated by the manufacture). The few minutes you lose making narrower strips will not kill your partner—having to re-search the entire avalanche might. Learn more about recommended search strip widths.
The following illustrations show the appropriate spacing for a 40-meter search strip width. Note that with a 40-meter search strip, you should get within 20 meters (half the search strip width) of the sides of the avalanche. When in doubt, go edge-to-edge.
As shown in the above-right illustration, if you have sufficient searchers, they can descend the avalanche path without zigzagging.
If the area where the victim was last seen is precisely identified, and the avalanche was small enough that the victim couldn't have been carried more than half the search strip width (i.e., about 20 meters) to the side of where they were last seen, you can search straight down the avalanche path starting at the LSA.
You should move quickly and deliberately during the signal search. Locating the initial signal depends more on choosing an appropriate distance between search strips than on transceiver skill.
Remember, the goal of the signal search is to receive a strong signal. If your transmitter receives a signal and then loses it (i.e., beeps a few times and then stops), or displays a distance without indicating the direction, you should continue the signal search, possibly with a narrower search strip width, until you receive a strong, consistent signal.