SNOWTAM.

How to interpret a SNOWTAM.


SNOWTAM and MOTNE RWY reports are only provided for winter conditions (snow, ice etc) but not for other hazardous RWY conditions e.g RWY slippery when wet or, wet combined with dust.
Observations and measurements are made at routine intervals but only when RWY are contaminated and/or when there are significant changes.

There are certain definitions used in SNOWTAM and MOTNE.
DAMP
The surface shows a change of color due to moisture.
WET
The surface is soaked but there is no standing water.
WATER PATCHES
Significant patches of standing water are visible.
STANDING WATER
Standing water of significant depth and area which affects the braking action (aquaplaning).
FLOODED
Extensive standing water is visible.
DRY SNOW
Snow which can be blown if loose. If compacted by hand, will fall apart again upon release.
WET SNOW
Snow which, if compacted by hand will stick together and tend to form a snowball.
SLUSH
Water saturated snow which with a heel-and-toe slap-down motion against the ground will be displaced with a splatter.
COMPACTED SNOW
Snow which has been compressed into a solid mass that resists further compression and will hold together or break up into chunks if picked up.


SNOWTAM example.

A)LSZH   B)11070620  C)10  D)2200  E)40L  F)4/5/4   G)20/10/10  H)30/35/30MUM  J)30/5L K)YES L  L)TOTAL  M)0900  P)YES 12  S)11070920  T)FIRST 300M RWY 10 COVERED BY 50 MM SNOW, RWY CONTAMINATION 100%

A)LSZH
AERODROME LOCATION INDICATOR

B)11070620
DATE/TIME OF OBSERVATION (in UTC)

C)10
RUNWAY DESIGNATORS

D)2200
CLEARED RUNWAY LENGTH, if less than published length (m).

E)40L
CLEARED RUNWAY WIDTH, if less that published. (m; if offset left or right of center line add "L" or "R").

F)4/5/4
DEPOSITS OVER TOTAL RUNWAY LENGTH (Observed on each third of the runway starting from threshold having the lower runway designation number).
NIL - CLEAR AND DRY
1 - DAMP
2 - WET
3 - RIME OR FROST
4 - DRY SNOW
5 - WET SNOW
6 - SLUSH
7 - ICE
8 - COMPACTED SNOW
9 - FROZEN RUTS OR RIDGES

G)20/10/20
MEAN DEPTH (mm) FOR EACH THIRD OF TOTAL RUNWAY LENGTH.

H)30/35/30
FRICTION MEASUREMENT ON EACH THIRD OF RUNWAY AND FRICTION MEASURING DEVICE.
MEASURED or CALCULATED COEFFICENT

0.40 and above
0.39 - 0.36
0.35 - 0.30
0.29 - 0.26
0.25 and below
9
ESTIMATED SURFACE FRICTION


5 - GOOD
4 - MEDIUM/GOOD
3 - MEDIUM
2 - MEDIUM/POOR
1 - POOR
9 - Unreliable
TYPE OF MEASURING EQUIPEMENT USED

BRD=Brakemeter-Dynometer
GRT=Grip Tester
MUM=Mu-meter
RFT=RWY friction tester
SFH=Surface Friction tester
(high pressure tire)
SFL=Surface Friction Tester
SKH=Skiddometer
(high pressure tire)
SKL=Skiddometer
(low pressure tire)
TAP=Tapley meter

J)30/5L
CRITICAL SNOWBANKS. If present, insert height (cm) / distance from the edge of runway (m) followed by L or R or LR if applicable.

K) YES L
RUNWAY LIGHTS (If obscured insert YES followed by L or R or both LR if applicable.

L) TOTAL
FURTHER CLEARANCE(If planned insert length (m) / width(m) to be cleared or if full dimensions insert TOTAL.

M)0900
FURTHER CLEARANCE EXPECTED TO BE COMPLETED BY...(UTC).

N)...
TAXIWAY (if no appropriate taxiway is available, insert NO).

P)YES 12
TAXIWAY SNOWBANKS (If more than 60 cm, insert "YES" followed by distance apart, m)

S) 11070920
NEXT PLANNED OBSERVATION/MEASUREMENT IS FOR (month/day/hour UTC).

T) First 300M RWY 10 covered by 50 mm
PLAIN LANGUAGE REMARKS (Including contaminant coverage and other significant information like sanding or deicing).