10. SNOW CLOSURE POLICY (SNOCLO) 10.1. Initiation
The presence of even small accumulations of wet snow can significantly affect the performance of aircraft. A plan to clear runway(s) will be initiated when the depth of accumulation is expected to exceed 3mm of slush or wet snow. The time of any snow closure will be notified to ATC and the airport community as far in advance as possible thus enabling operators to manage pushback, turnaround and de-icing activities in the most efficient manner.
Flight operations may continue until such time the runway is formally closed for snow clearance, however, once snow has started to accumulate continued operations will necessitate frequent inspections of the runway to ensure accurate surface state reports are available to pilots. Surface State reports will include the coverage, type(s) and depth of contaminant present in each third of the runway, as described in Section 2.1. The decision to close a runway will account for the need to remove contaminants from the runway surface in a manner which minimises operational impact, but considers the risk that any accumulations of slush, standing water or wet snow may freeze if left untreated.
10.2. Light Snowfall
During or after a light snowfall, experience has demonstrated that a period of approximately 90 minutes is required to clear and anti-ice each runway. In these circumstances a ‘SNOCLO message’ will be issued by SNOWTAM & NOTAM with an expected duration of 90 minutes. This will be accompanied by an SMS message to the “major disruption” and “weather” groups and displayed on the Chroma Fusion system.
10.3. Prolonged or Heavy Snowfall
During or after heavy snowfall, a longer duration of snow closure may be necessary. In these circumstances, a ‘SNOCLO message’ will be issued by SNOWTAM & NOTAM promulgating the expected duration of closure. If circumstances dictate, the ADM and Snowman Airfield will consider the need to extend the estimated closure duration. This decision will be agreed between the ADM and Crisis Management Centre (if active). The ‘SNOCLO Matrix’ in Appendix H details and estimated period of airfield closure dependant on the depth of snow accumulation present on airfield surfaces.
10.4. Runway Possession
Whilst snow clearance is in progress on a Runway, the Runway will be closed by ATC and will remain under the control of Snowman Airfield. The remainder of the Airfield Manoeuvring Area will continue to be under ATC control. The Runway will remain closed until sufficient clearance of the Priority 1 Areas detailed in Section 11.1 and appendix B have been completed to allow safe operations to resume.