Tiered Snow And Ice Response

The Street Division has developed a tiered response to ensure efficient clearing of streets during a winter weather emergency.

Types of Streets

Primary Snow Routes

These streets are plowed first because they link the city's police, fire and emergency services.  Primary snow routes are major thoroughfares used by thousands of motorists and cyclists every day.

Secondary Snow Routes

These streets are highly traveled by motorists and cyclists, but not as much as primary routes.  Generally speaking, these streets feed into the Primary snow routes.

Hill Routes

These streets have a grade of 8 degrees (14% slope) or greater and a configuration which makes them extremely difficult to navigate.

Residential/Side Streets

These streets are generally narrower than primary/secondary routes and carry significantly less vehicular and bicycle traffic.

Find more details on the snow routes map.

What to Expect in Our Winter Storm Response

Phase 1

When storm/ice is forecasted AND no lead-in rainfall is expected, primary and secondary snow routes are pre-treated with brine to slow down the freezing of precipitation on the roadways. If time allows between the time the storm is forecasted and the start of precipitation falling, we will also pre-treat the hill routes.

Phase 2

Once snow begins to fall, crews begin to plow primary, secondary. We have 2 crews working 12 hour shifts if necessary. If precipitation is ice (vs. snow) crews will be spreading salt on the snow routes.  As long as precipitation is falling we will remain in Phase 2, meaning there will be little to no treatment of non-snow routes.  During Phase 2, the Citizens' Service Bureau will be advising citizens to give our crews time to respond to the event before they will accept requests for treatment of trouble spots.

Phase 3

St. Louis can have a wide variety of snow storms, from 2-3" in a day followed by temperatures in the upper 30's to 10-12" in a few hours followed by below freezing temperatures.  Phase 3 depends largely on the forecast and the type of storm.  Regardless, phase 3 does not begin until precipitation has stopped falling.

  • After finishing primary and secondary routes, crews will begin clearing the hill routes. Bicycle lanes on primary, secondary and hill routes will also be cleared during this phase.
  • If snowfall is of a significant amount that plows are creating a deep windrow of snow across intersections, crews will be dispatched to push that snow out of the intersection.
  • If temperatures are forecasted to remain below freezing for several days, crews will salt and/or sand residential intersections as needed to ensure safe stopping.
  • Crews will respond to trouble spots reported to the Citizens' Service Bureau, treating with salt and/or sand as needed.
  • In many events the snow stops falling after several hours and within a day (or later the same day) temperatures warm and non-snow routes begin to see pavement simply from traffic moving.In these cases, there is no Phase 3.


Related Links

Snow Route Map (download)
Resources for Street Treatment
Snow Route Interactive Map
Citizen Role in a Winter Storm
Snow Driving Tips

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