Well, we are not having the floods of Queensland, although our location on top of the escarpment is equivalent to that of Toowoomba.What we are getting is grey, misty skies. Sometimes raining, sometimes leaking watery sunlight through the clouds.
It is difficult to make Robertson's weather sound "romantic". The best I can say is that in Robertson we do "ordinary" weather "extraordinarily well".
This month, our rainfall has been consistent, but not dramatic. Rain, alternating with mist, drizzle, more mist, rain and fog.The rainfall so far this month has been: 0; 2; 0; 4; 0; 0.5; 0; 15; 7; 24; 24; 43; 1 (all in mm).
Unlike the Inuit people of Greenland (who according to Peter Hoeg, in "Miss Smilla's feeling for snow" ) have more than twenty different words for snow, we Robertson people do not, but we can go close for different words for fog.
Well, actually we could if we were a more literate society (instead of a Potato-growing, Rugby League-obsessed community).
I measure the fog by the visibility factor - how far I can see through the fog.
There is a standard measure. Aircraft pilots have defined fog and mist as follows:
"Fog is visibility less than 1000 meters and mist, by definition, is visibility between 1000 and 5000 meters. Both have their origins in light suspended cloud droplets with a nearly 100% relative humidity and an abundance of condensation nuclei."
Are they kidding?
That's not a real fog - not in Robertson, anyway.
Visibility reduced to 5 Kms approx (beyond Belmore Falls)
I measure Real Robertson Fog in terms of
those trees which are the furthest away which I can see from my back deck.
- If the trees at the Cemetery (800 metres away) disappear, that is a light fog.
- if the Power stanchion in the next paddock below my house, disappears, that is a medium fog, or more likely, a heavy rain cloud rolling in from Kangaroo Valley.
Visibility reduced to my back paddock - 200 metres.
|Bright light, medium fog|
|Medium-thick Fog - today|
- There is another complication - the depth of fog directly above me. In other words, is the fog really part of a dense cloud? If so, it dramatically lessens the available light. So I can have a bright fog, a dull fog, or a dark fog, depending not on the "density" of the fog itself, but the amount of light coming through the clouds above. Sometimes the light in a fog can be so bright as to almost cause "white out". Yet it can still be a thick fog.
- Of course, there is yet another factor - I can have clear air (in my immediate vicinity) but be looking at a wall of fog rolling up the valley. That is illustrated in the series of photos in the blog post from October 23, 2008.
- If the furthest tree I can see is the Sassafras growing 30 metres from my house, then, and only then, do I rate that as a true thick Robertson fog.
DRIVING IN FOG?
I suggest you take note of the white road "dividing markers" kindly used on the main roads in the Robertson area by the RTA. Because we are an area known for experiencing fog, they are very strict in ensuring our roads are marked.
- According to Table 4.1 in that document linked above, the white lines are 3 metres long, and spaced at 9 metre intervals.
- If you can (just) see the next white line mark, you have a fog visibility factor measured at 12 metres. Two white lines, means you can see out to 24 metres. Either way, that is a serious fog and it is a definite road hazard.
|VISIBILITY APPROX 24 METRES - SLOW DOWN|
- If you are driving in such a fog, my advice would be:
- Adjust your driving speed according to the conditions.
- Slow down,
- Put your head lights on (even in daylight).
- Experienced local drivers use their hazard lights (blinkers).