Looking for the lost phone

My son decided to film his sleigh-ride while going down the mountain. He forgot to look where he was going resulting in a ride into the snow. The phone flew out of his hand into the 4 meter deep snow.
We looked for a while, but as the phone was on silent we couldn't find it. When we gave it a last chance my son could feel the vibration from the phone underneath his one foot. We started digging and there it was. And working properly.