Buzzman has excellent advice, but is inaccurate regarding snowplows.

<<<<Snowplow drivers are super dangerous. Don't mess with them. They have often been driving the plow in horrible conditions without sleep for 24-48 hours and are soused in coffee and possibly worse>>>

Most municipalities have strict regulations limiting a plow shift. In MN this is usually 12 hours. Some are 16. The drivers aren't dangerous; the conditions are. Drivers are required to take extensive training including accident awareness and mitigation. Not sure what he means by, "soused in coffee and possibly worse". I suppose anything is possible, but to retain a class B commercial license I would not suspect the driver to be soused in "possibly worse".
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To the OP's question, the cloud they create exacerbates the existing low visability. Don't rely on your lights and rear blinkies to make you noticed. If you see one coming up on you, run up a driveway. If a driveway is not available, walk your bike well past the shoulder into the ditch. The minor inconvenience is short and worth your safety.
Fortunately, the few encounters I've had, the driver had seen me and slowed down to lessen the velocity of the muck headed my way.