https://www.cnet.com/roadshow/news/waymo-machine-learning-self-driving-cars-snow/

Five minutes into a harrowing cross-state winter drive, I received a warning on the dashboard. All my front-facing sensors and cameras were obscured with ice, rendering the vehicle's numerous active safety systems disabled. Winter can make it extremely hard for sensors to do their jobs, but Waymo has a trick that my car didn't -- machine learning!

At this week's Google I/O conference, Waymo discussed how it uses sister company Google's developments in machine learning to help its self-driving vehicles navigate snowy climates. Snow shows up on Waymo's sensors as noise -- a giant purple cloud of object-obscuring noise. If a vehicle actually thought solid, unmoving objects surrounded it, the vehicle would stop and resume travel in the spring.