SNOWTAM and the runway surface condition

A SNOWTAM is not a weather report but a surface condition report for the movement area. Since the introduction of the globally harmonised reporting format, what sits at the centre of it is no longer a braking-action figure but a code for each third of the runway.

Applicability: European Union (EASA framework), on the basis of the ICAO reporting format
Rulemaking authority: Commission Implementing Regulation (EU) 2017/373, Annex VI (Part-AIS), Appendix 3 (SNOWTAM format)
Reviewed by NorthTrack on: 2026-09-13

SNOWTAM – the definition
A NOTAM of a special series, in a standard format, providing a surface condition report notifying the presence or cessation of hazardous conditions due to snow, ice, slush, frost, standing water, or water associated with snow, slush, ice or frost on the movement area. (In substance, after Article 2(231) of Regulation (EU) 2017/373.)

The name
The report is called a SNOWTAM. "SNOWMET" is not a type of aeronautical message.

The abbreviations in a SNOWTAM

SNOWTAM — Snow NOTAM *
Valid for no more than 8 hours; every new SNOWTAM cancels the previous one.
NOTAM — Notice to airmen
The general form of message the SNOWTAM is derived from.
SW — Data designator for SNOWTAM
The first two characters of the abbreviated heading TTAAiiii.
RWYCC — Runway condition code
One digit from 0 to 6 per runway third, for example 5/5/3.
NR — Not reported
Stands for a runway third for which no information is available.
DRY — Dry
A contaminant description; DRY is the only one where the coverage figure is omitted.

* The English expansion of these codes is defined only in ICAO Doc 8400 (PANS-ABC). That document is not freely available, so the expansion has not been verified against the primary text for this edition.

Validity and replacement

The maximum validity is 8 hours.
A new SNOWTAM is issued as soon as a new runway condition report is received – so regardless of whether the 8 hours have expired.
A SNOWTAM cancels the preceding SNOWTAM. There is only ever one in force.
Metric units are used, and the unit itself is not reported.

All four rules are in Appendix 3, point 1 of the Regulation.

The runway condition code (RWYCC)

The core of it is one figure per runway third – the touchdown zone third, the midpoint third and the roll-out third, read in the direction of the lower runway designator. For each third exactly one digit from 0 to 6 is reported, separated by obliques (Item D, in the form n/n/n).

6 — dry runway
5 — good braking action
4 — good to medium
3 — medium braking action
2 — medium to poor
1 — poor braking action
0 — less than poor – braking action effectively absent

Assigning a code to a contaminant is done at the aerodrome using the runway condition assessment matrix. The classification shown here is for understanding the scale; what governs are the aerodrome publications and the aircraft documentation.

The code is supplemented by a description of the contaminant for each runway third (Item G) and, where the contaminant is not DRY, by the percentage coverage in steps of 25, 50, 75 or 100 per cent for each third (Item E). Where an entry is absent it is reported as NR – not reported.

How the report is built up

The report consists of an abbreviated heading, a section for the aeroplane performance calculation and a section for situational awareness.

The heading

The heading takes the form TTAAiiii CCCC MMYYGGgg (BBB):

TT — data designator for SNOWTAM – always SW
AA — geographical designator of the Member State
iiii — four-digit serial number of the SNOWTAM
CCCC — four-letter location indicator of the aerodrome
MMYYGGgg — month, day, hour and minute of the observation, in UTC
(BBB) — optional COR for a correction to a message already disseminated under the same serial number

The aeroplane performance calculation section

A — aerodrome location indicator
B — date and time of the assessment
C — runway designator (the lower number)
D — runway condition code for each runway third, n/n/n
E — percentage coverage for each runway third, 25/50/75/100
F — depth of loose contaminant for each runway third
G — description of the contaminant for each runway third
H — width of the runway the codes apply to, where less than the published width

Where there is more than one runway, items B to H are repeated (Appendix 3, point 1(a)).

The situational awareness section

Items I to T describe, among other things, reduced runway lengths, snowbanks, the condition of taxiways and apron, and additional remarks in plain language. Elements for which no information exists, or whose conditions are not met, are omitted entirely – so a missing item does not mean "unknown", it means "not applicable".

What this means for general aviation

SNOWTAM are issued above all at aerodromes with commercial traffic. At smaller fields the information comes by NOTAM, from the aerodrome operator, or not at all.
The RWYCC is tailored to the aeroplane performance calculation. Whether and how a code affects a particular type is stated in that type's approved documentation.
A code of 6 means "dry", not "safe" – crosswind, runway length and obstacles are independent of it.

Take-off and landing distances can be worked through in NorthTrack with the figures for your own type. Open the performance calculators

Official sources

European Commission / EASA: Commission Implementing Regulation (EU) 2017/373 (Annex V "Part-MET", Annex VI "Part-AIS") – Consolidated version 02017R0373-20250501. Open source (retrieved 2026-09-13)
DFS Deutsche Flugsicherung GmbH: Aeronautical Information Publication Germany – AIP VFR, GEN 2-1 to GEN 2-7 "Abkürzungen / Abbreviations" (bilingual German/English) – Effective 20 AUG 2026. Open source (retrieved 2026-09-13)
ICAO: Doc 8400 – Procedures for Air Navigation Services: Abbreviations and Codes (PANS-ABC). Named by Regulation (EU) 2017/373 as the reference for the meaning of the weather abbreviations. – —. Open source (retrieved 2026-09-13)