Monday, 3 August 2020

Working through the alphabet

It is common practice to have a Plan B.  Advanced project managers also have a Plan c.  In the Census program our fall back was always Plan D: when Plan C falls over, immediately construct Plans E and F.
  For 2 August I think we certainly visited Plan D and implemented Plan F (or possibly G - I lost count.

By way of background our electricity supplier advised (some weeks ago - this is GOOD) that they were having an outage for about 6 hours on 2 August to fix up some major issues.  So we thought this wood be a chance to go an explore a few areas.  

The first thought (ie Plan A) was the Errinundra National Park.  Then in conversation with a friend it appeared the roads in that area were rather ordinary at best and after the fires and a lot of rain like to be very ugly.  They suggested an area North of Orbost as a better option (plan B).  

Consulting Google Maps suggested 
  1. that was close to 4 hours driving each way, by the shortest route; and
  2. said route went through NSW.
Point 1 knocked that plan down and point 2 administered the coup de gras.  Plan C focused on Bemm River which seemed reasonable until we consulted some touring maps which gave a lot of attention to the Point Hicks - Tamboon area.  So Plan D was to go to Point Hicks and if that was a fizzer, Plan E was to call in at Wingan Inlet on the way home, having filled up with diesel at Cann River.

The first issue was that as we passed through Cann River the Shell servo appeared to be closed (the low price United servo has been demolished for some reason).  I was confident we had enough fuel for Plan D so carried on.

A subset of Plan D emerged when we found that the road to Point Hicks was closed (locked gate as well as a stupid notice by Parks Victoria, where the red line meets the blue).  However the road to Tamboon was open so we veered in that direaction.
The Inlet at Tamboon was quite attractive and seemed to be popular with camping fisherpersons.  I could actually say fishermen as I didn't actually see an obviously female person there.  Further, they all looked characters from a well known film about a canoe trip: I suspect the sound of banjos would have been very evident in the evening
A few birds were evident including this very tight raft of coots.
This large map was evident extolling the delights of various tracks, including one to the sand dunes - which are the main attraction (other than fishing).  
However the map didn't show any tracks; there was a sign saying "No access to water" past the camp; and the edge of the Inlet was soft, slippery mud.  I asked one of the aquatic persons how to get to the sand hills and they said either go along the edge or take a boat!  End of Plan D.

Plan E was to head back towards home checking the Genoa Falls and Gipsy Point Cemetery as we went.  A side trip to Wingan was ruled out as we were unsure about fuel with a further 60+kms added on,  As we left I pulled over and eventually took a photo of the road.
Why do I say eventually?  The answer lies in the vehicle seen on the road.  It was Plod - and I must say very Pleasant Plod who were patrolling the area and just wanted to check we were "All good?".  They couldn't tell us of any walking tracks in the area but did say that there was a 24 hour, card-only BP servo on the Monaro Highway in Cann  River that was always open.  Very good guys!

We took the snap and rumbled off .  We paused briefly to photograph this Epacris growing beside the road.  Checking the Flora of Victoria suggested that only E. impressa had flowers other than white.  However this was far larger than any other of that species.  A mystery.
We checked the Shell servo and they had a sign saying "Closed due to fuel outage".  Frances had wondered about but had dismissed the thought as all servos had generators.  Obviously at least one did not have a gennie.

Plan E.1 included a stop at the Drummer rainforest walk to eat our lunch.  A nice colony of Earthstar (Geastar sp.) fungi were evident.
Getting into the rainforest we found a colony of these little furry bracket fungi growing up a tree trunk.
The track crossed Drummer Creek several times.

That image is interesting as the bridge was untouched by fire while the first bridge - on the transition from eucalypt forest to rainforest - was a little compromised.  Judging by the footprints many people were walking the track.  

There were many magnificent trees.


Being rainforest there were many epiphytes.
The second stage of Plan E was to call in at Genoa Falls on Genoa Creek to check the flow. The official gauge at the Gorge on the River (a few kms from this point on a different watercourse) was down to exactly 1 m (from a high of 2.4 m) so the flow was less spectacular than it would have been during the week.


Towards the end of the rocks a pool was attracting the foam (a nicer word than scum) in an interesting pattern.  It looks fractal, but I'd like to see someone give a simple formula (like zn+1 = zn2 + cthat generates that!
We swung into Genoa to look for Emus but none were visible.  There were none.  But there were a few Shelduck and a good flock (36 birds) of Little Ravens.  On the Flats on Mallacoota Rd we found 22 Straw-necked Ibis (which never seem to make it to Mallacoota..  Overall I recorded 22 species here https://ebird.org/australia/checklist/S72030965.

Talking of fractals and the Mandelbrot set, leads to chaos theory: some elements of the day approached that but iverall it was quite enjoyable.  The worry is the amount of work to be done by Parks to open up the National Parks.  It is now more than 7 months since the fires and nothing seems to have really happened other than a few teams of contractors knocked over a few trees.  



Saturday, 1 August 2020

July Weather Report

You may have noticed that the weather was a little damp this month.  It was also quite mild.  This report may be quite brief as Blogger seemed to have an HTML cow with my first attempt and I am not sure how I will go on recovering it.  (It seems to have worked OK.  No idea what the problem was but Blogger has been updated to appear better on mobile phones and as usual that has mucked up stuff on computers.  And Google seems unwilling to listen to such heresy.)

Rainfall

A very wet month at Mallacoota. We totaled 170 mm at home.   A very significant amount above the median and 2019. The Airport managed 151 mm: the sixth highest July reading (out of 42) at the current site.
We experienced 2 significant rain events during the month.  The first, from the 12th to the 16th, amounted to 52 mm. The second, from the 26th to the 31st, brought 105.4 mm
In terms of impact on the water level in the Inlet the falls in the hinterland are also important.   There seems to be no weather station actually in the Mallacoota Inlet Catchment (including both Genoa and Wallaraugh Rivers) which provides time series data.   However the BoM station Bombala AWS, while situated in the Snowy River catchment, is not far from the upper catchment of the Genoa River and seems to serve as an indicator of upstream falls   At that site the falls in the first event were approximately double those of Mallacoota sites while the opposite applies for the second event.
Only short term data for the flood level gauge at the Genoa River is available from the BoM site on line.   What is available at the time of posting (1 August) shows the River at~2.4m, which is above minor flood level, on 28 July but dropping to 1.12 m by the end of the month
The impact of the rainfall from the 2 events is clearly shown in a chart of the heights at the official gauge at Mallacoota Wharf.   Following the opening of the Mouth readings here are influenced greatly by the tide and if the wind is pushing ocean water into the Inlet.   However the impact of the flood peak in elevating water levels on 28 July is very clear.
Compiling a prorata estimate of the annual rainfall shows a nice uptick this month with the estimate at the end of the month at an annual total of 957 mm.

Temperature

The overall picture was above average minimum temperatures and below average maximum temperatures.   That combination of extremes occurred on 18 of 31 days in contrast to the expected occurrence of 7 days.   This can be expressed by the anomaly (current average-long term average) on +0.68C.  The progress of the anomaly through the month is illustrated in this chart.
My second overall view of temperature is the daily extremes.   Fairly bland with no runs of unduly hot or cold.

Maximum Temperatures

The average maximum temperature (15.27C) was a little above average but a fair bit below last years average maximum.   The latter is almost certainly due to this year being very wet and thus cloudy while last year was a tad arid.
The average monthly maximum series is a bit bouncy but the linear trend line is well below the level of significance
I am noticing that the average maxima I am generating at home are quite consistently a degree or so above those at the airport.   This is quite readily explained by the impact of afternoon sea breezes cooling the airport more than here,   I shall research this a little more and probably adjust my historical series.   Expect an ad hoc post in the near future.

Minimum Temperatures

Quite a warm month overall for average minimum (7.89C), as a result of the cloud blanket!   Also I expect to find a much higher proportion of the wind reading coming from the sea rather than the land.
The trend line for the minimum time series is a close to flat as could be expected.   I shall check the comparison with the BoM data but for this month at least they are in close agreement.

Humidity

A large amount of rain is - possibly by definition - associated with high humidity,   And so it was this year.   The two periods of heavy rain are identifiable as the days on which the 0900 and 1500 humidities are close to identical.
For both time periods the 2020 value is well above the 2019 and longer term average values.

Wind

The month was quite moderate for wind.   The day (13th) with the longest run (246 km) was the 31st longest run of the 536 days in my records.   Overall the run was a little less than last year and a fair amount less than my long term indicator.   (Note that home is a lot less windy than the BoM site so I have adjusted the BoM data.   A crude adjustment but in this case I have little other data to go on.)
In terms of the direction of the wind the rose shows that a very high proportion of the wind came from the Western half of the compass.
In an earlier post about the heavy rain event of 26 -30 July I showed how once the low actually arrived the wind settled down to blow from the ESE (with occasional strong gusts from the NW as mini-cells came through).  A similar pattern was also evident in the first wet period.  I haven't been able to work out how to show that in a graph but, trust me, nearly all the wind from the Eastern half of the compass came from the core days of those systems.

Friday, 31 July 2020

Beaches

Following the departure of the coastal low we have visited the local beaches expecting to find many interesting things washed up.  Cutting to the chase, the flotsam was not that diverse: mainly seaweed.  However there was interest in seeing the water running out of creeks and the erosion.

Getting to Bastion Point the immediate interest was the mound of foam at the waters edge.
When we left the beach an hour later we saw the corpse of a very large fur seal right beside the steps.  I haven't included a photo as its a tad gruesome.  However I am curious as to why we didn't spot it on the way down.  Either (1) I was distracted by the foam or (2) the foam covered the body..  It will start to get stinky so has been reported to Parks.

There was more foam further down the beach.
The mouth was now quite wide and flowing very strongly.   The outgoing water was very brown: whether this was due to sand being carried out or just tannin in the run-off was unclear to me.  It meant the waves were brown all the way to the steps, and for a long way out to sea.
The next day we went to Davis beach to look at the now open Davis Creek.  The Creek opening was not greatly exciting but the amount of erosion was fairly spectacular.  This bank was 2 m high in places..
While at the Creek we were entertained by 2 sub-adult White-bellied Sea-Eagles.  They didn't dance but just soared looking attractive.  Both photos are the same bird: the second appeared too far away to get a decent picture.

Close to the Creek opening we were interested to see the various black layers visible in the exposed face of the dune.  As there has only been one recent huge source of ash we assume this reflects the way the sand has built up this year with rain events washing ash and charcoal out to sea and subsequent high constructive tides covering it with clean sand.
Going along the beach to Betka the only debris of interest was a much higher than usual number of Cuttlefish 'bones'.  When we got to Betka the water was flowing back into the estuary, reflecting the incoming tide (and presumably the run off into the River having calmed down.
Certainly the road bridge was well out of the water.


Wednesday, 29 July 2020

Low, and on the East Coast

This post is about the weather event of 26 to 28 July 2020.  I have done another post with some images of the impacts of the rain etc.

I have used the title of this post since the BoM seems reluctant to call the event an East Coast Low (ECL).  They have a fact sheet about such events and this event seems to tick (at least) most of the boxes for an ECL and doesn't match any of the other possibilities in that sheet.  Discussion (by meteorologists) on a forum I follow seems to conclude that this is actually an ECL - they have information that the crucial attribute (of upper level events impacting on surface level events) has happened.  

Whatever one calls it we had a lot of rain - 104.6 mm and counting - such that we are now (0640 on 29 July) 25.4mm (1 inch in old money) above the pathetic total in 2019.  Doing a pro-rata estimate for falls to date my guesstimate for 2020 is 960 mm, the highest since 2016.  

I will begin with a chart of the hourly rainfall from midnight 25 July to 0700 on 28 July.  (A small amount has fallen since then but it doesn't greatly change the picture.)  
Another way of looking at this is the cumulative amount that has fallen.
The rain was quite steady with only a couple of spikes in the rate.  Knowing that my WS has recorded some squalls well over 100 mm/hr I originally rated them as quite modest at around 70 mm/hr.  However looking at the detail shows these to be about the 16th and 17th heaviest rates (out of 16,000 observations)
Looking at the wind is interesting.  As always I am a little tentative about wind readings as the wind exposure of my WS isn't ideal.  

There didn't seem to be any outrageous gusts (37 kph was the strongest gust and the longest hourly run was only 11.2 km).   However the direction of the wind produces a somewhat strange chart.  In the lead up to the low getting down this way any of the wind observations are from the NNW (bearing 337.5 degrees).  However once the low arrived the wind settled down to ESE (112.5 degrees) with a few gusts from the SW (225 degrees) presumably reflecting the passage of embedded cells. 
A key factor of low pressure systems ins the low pressure (duuhh).  This chart shows the pressure dropping from around 768 mm until about midnight 27 July when it settled down around 758 mm for the rest of the period of recording.
The centre of the system was somewhat North of us.  By way of example, Ulladulla, 260km NNE of Mallacoota, copped a real downpour.
A chart of the accumulation shows the steady rate of rain.
The ultimate impact of the rain is to boost the inflow to the Inlet.  Here is the BoM gauge at Genoa River Gorge.  The rise was from 075m to 2.40m: as indicated it was above minor flood level from several hours.