The initial actions following an avalanche accident are primarily to ensured the scene is safe, to obtain situational awareness (e.g., determine the number of people who were buried), and to do an initial visual search.
After the people who were not buried are in a safe location (aka an "island of safety"), everyone should switch their transceivers to search mode. (After the victim is extricated, everyone should return to transmit mode.) If I had a nickel for every training that stumbled due to a transceiver remaining in transmit mode...
It is important to understand that many transceivers will automatically switch back to transmit mode. This can cause confusion when unburied members of the party unknowingly begin transmitting.
One trick to determine if a signal is coming from a rescuer on the surface is to stand still while you are in search mode. If the distance or direction that is displayed on your searching transceiver changes while you are stationary, you are receiving a signal from a rescuer who is moving on the surface.
You should also turn off any electronics that might interfere with your transceiver (including your GoPro and heated gloves). If you can't turn off your electronics, move them at least 20 inches (50 cm) from your searching transceiver. If someone is talking on a cell phone or radio, they should be at least 20 meters away from you.
There are three steps during an avalanche transceiver search:
It is wise to periodically read the owner's manual that was supplied with your transceiver to learn model-specific nuances. And you must practice frequently.
Special techniques are required to locate multiple victims. Those techniques will vary based on your training and the type of transceiver you own. Locating multiple victims is much more difficult. It is always better to use safe travel techniques that limit the number of people who are exposed to the avalanche hazard.
Shortly after the dust settles, it is important to do a visual search for clues. That visual search should continue as you search using your transceiver. One method of doing this is to look at the displayed distance on your transceiver, look at the direction indicator, look at the snow around you for clues, and then repeat this three-look process. Think "distance, direction, look up."