Tires

It depends on where you live. If you get substantial snow accumulation and you must drive on snow-covered roads, then dedicated snow tires will be the safest tires you can have on your car. In general stock OEM tires that come with Prius are geared toward improving efficiency thus do not provide the best traction in inclement weather. But if you live in an area that sees little or no snow or the road you usually drive are always quickly plowed and salted, then you may be able to get by without dedicated snow tires.

 

I live in Maine. Where I live our rivers, lakes and ponds normally freeze over every winter and we drive across them on the ice. Also When the ground gets below freezing, If there is any ground fog [coming up from the rivers] that fog will freeze onto pavement forming a phenomenon known as 'black ice', it looks like clean black pavement but it is as slick as an ice skating rink.

We go through the winters on studded snow tires.

Studds are legal here from mid-October until mid-April of every year. I just swapped off my summer tires in favor o fmy winter tires this past week.

I normally drive on ice. To do so safely I must have studded snow tires on my car.

I did not see a location on your post, I do not know where you live. If you normally see temps much below say -20F in the winter, then yes you need much better tires.

If your winters will only be down to 30F, then you may not need a separate set of tires for winter driving.

 

The photos from that angle show us nothing. How deep is the tread? Use a small ruler to measure the depth of the groove between the tread blocks, or stick in something to measure it. Tread depth is measured in 32nds of an inch (or in millimeters). Most states require a minimum of 2/32" for dry or wet roads and 4/32" for snow use. Deeper is better. I never let my tires get down to 2/32"

If you are concerned about snow traction, look for one of the new all-weather tires that are all-season with a severe snow service certification. They include the Toyo Celcius, Michelin CrossClimate+, Vredestein Quadtrac, Goodyear Assurance WeatherReady, Firestone Weathergrip, General Altimax 365 AW, Hankook Kinergy 4S2, and others. These are suitable for year-round use.

Here is a depth guide from Goodyear: