CRJ-900 Captain reported an apparent failure of the Type 1 and Type 4 deice and anti-icing fluids that had been applied to the aircraft during a heavy snowstorm pre-departure. After noting significant snow accumulation on the wing the crew returned to the gate and noted numerous other aircraft had done the same.

Narrative

This report is to document a widespread Type IV fluid failure in heavy snow; which affected my aircraft among dozens of others. The METAR at the time our deicing process began read 06011KT 1/4SM R03R/1800V2400FT +SN FG VV004 01/M01 A2957. Type I fluid was applied to deice; followed by Type IV to anti-ice. The fluid was Clariant Safewing MP IV Launch at 100% concentration. During taxi from our gate to the deice pad; the FO and I noted the severity of the snow storm in progress. While taxiing from XX approaching XY; we experienced NIL braking action; wherein I had fully applied both brakes and was seeing no deceleration; requiring the deployment of both thrust reverser's in order to stop the aircraft. Eventually we made it to the deice pad. During deicing; we observed and notified the crew of an A321 that had just finished deicing that they appeared to have a Type IV fluid failure; with snow accumulation covering the portion of its right wing to the left of the engine mount. That crew appreciated our report and returned to the pad for a second round of deicing. Once our deice crew had applied our Type IV fluid; we ran our post-procedure checklist and proceeded a short distance from our deice pad assignment to a nearby taxiway; where the A321 had been sitting earlier; which paralleled our departure runway. We were in line behind another Regional Jet which had just completed deicing as well; and we could already see that this aircraft's Type IV fluid had failed. Snow had already accumulated on both of its flaps and winglets. The FO (First Officer) and I had already briefed that we would conduct an inspection of the Type IV fluid from the cabin prior to takeoff. Rather than wait until we were closer to taking off; we elected to conduct the inspection earlier than normal; due to the evidence of widespread Type IV fluid failure with other aircraft. While my FO was in the cabin; I took a look at our left wing from my vantage point in the flight deck; and observed that the Type IV green dye had already dissipated substantially; with snow beginning to accumulate in those areas. Not surprisingly; my FO returned about 3 minutes later; advising me that it was evident the Type IV fluid had already failed on both wings; and especially on the right wing; where snow was now blanketing the entire surface. During that time; the Regional Jet in front of us had advised Ground Control of the same. Eventually; the A321; the Regional Jet we were behind; and us all returned to our gates; citing a Type IV fluid failure as the cause. Numerous other aircraft from other deicing pads stated the same.The cause of this event is heavy snow overcoming the protective qualities of Type IV anti-icing fluid. Given the time frame between the start time of the anti-icing fluid application and the observed failure of that fluid; I do not have any confidence in our Flight Operations Manual's assertion that our aircraft may safely depart in heavy snow. While the manual requires a pre-takeoff check; after this experience; I believe we should err on the side of caution and further study when dispatching in heavy snow is reasonable. I do not believe doing so when the temperature is hovering just above freezing is advisable; as the snow appeared to have a water content that easily and quickly defeated the Type IV fluid.This event will recur given the same weather conditions; absent a change in dispatch procedures during heavy snow events; or a change in a more resilient fluid for use in heavy snow conditions.