If your computer isn’t within your punching range, SteamVR has a built-in feature for this, called “Knock Knock”. Right click the headset in the SteamVR desktop UI to get to it. It puts a button on your desktop that lets someone click it to alert you in the headset.
LiDAR in particular actually kinda sucks at those conditions (basically any form of precipitation). It’s really only good in clear environments.