Crikey it’s wet

[onetrack]

We've just had a pretty violent low pressure system move through the SW of the State, bringing much needed rain, along with strong winds.

 

The BOM got a bit hysterical yesterday with a Severe Storm Warning, talking up a "one in 5 year storm" with 125km/hr winds, but the winds weren't quite that bad, with a number of areas around Perth and the foothills recording 98km/hr maximum wind gusts, with average wind speeds probably around 65-80km/hr.

 

The SW Capes - Cape Naturaliste and Cape Leeuwin, recorded 109km/hr and 119km/hr maximum gusts, and Busselton Jetty recorded 109km/hr as a maximum gust.

Rainfall overall was between about 10-25mm, with most inland areas receiving useful falls, although a few strips missed out and only recorded 6-8mm.

 

There's the normal amount of Winter storm damage, a good number of trees down, a few sheds and sheets of iron went flying, and there's a few thousand people without power this morning.

No damage to report here at home, although the fruit trees took a pummelling, there are mandarins and limes everywhere in the backyard, although the orange tree is O.K. They're all in full fruit, of course, as expected for this time of year.

 

Edited yesterday at 02:13 AM by onetrack

[facthunter]

Perth is often called the Windy City.  Nev

[onetrack]

We've certainly earned that moniker well and truly today. The wind is still screaming, and looks like keeping up for a while yet. They had a gust of 102kmh at Swanbourne, and gusts of 133kmh and 135kmh at the Capes this afternoon. Rottnest Island recorded a gust of 113kmh just before 3:00PM, but it looks like the wind knocked the recording station out, it's currently offline.

This is the most intense low pressure system I've encountered for quite a while, so maybe the BOM was right about it being a 1-in-5 year storm. My SD is currently without power in Stoneville, up in the Hills.

[onetrack]

This is local news from this morning, the weather has taken a turn for the worse this afternoon. 

 

https://www.watoday.com.au/national/western-australia/wa-storm-leaves-thousands-without-power-across-the-state-20260531-p602e9.html

 

https://www.abc.net.au/news/2026-05-31/intense-storm-hits-wa-thousands-without-power/106741236

 

It's not being helped much by the current full moon causing high tides. So with the storm surge, a lot of places along the Swan River are under water.

 

Edited 22 hours ago by onetrack

[facthunter]

I don't think being a full moon causes the Highest tides.  It indicates the sun is on the Other side of the world. How low did the Barometer get? It's worth while Having one in your House to note it's readings and Movements. They last a long time. Nev

[facthunter]

On one occasion at PH the Ansett plane before Me landed and sat there clear of the runway. TWR said you are clear to taxi to which he replied, No I'm just going to sit here and watch TAA Land. It was by far the Most violent air I've ever flown in. The B 727 Has Massive control authority with spoilers  as well as ailerons, all hydraulically controlled and using thrust as well for Airspeed control. Nev

[onetrack]

Yes, a full moon does create higher than normal tides - but the tide height is also dependent on whether the Moon (or Sun) is at perigee or apogee, and whether the Sun and Moon and Earth are fully aligned.

The Moon is currently close to perigee, so its gravitational pull is higher than it's been in recent years.

 

Re the barometric pressure, Busselton Jetty weather recording instruments went off line in the storm, but Busselton Airport recorded 989.9hPa at 7:00 on 31/05, so a reasonably intense low.

The centre of the low was well S of Albany, and it appeared to be around 987hPa at its centre. In Perth, we recorded 997.1hPa at 4:00AM on 31/05.

 

Edited 6 hours ago by onetrack

[facthunter]

The closeness of the Isobars gives an indication of the Wind velocity (Pressure gradient).  Yes high tides occur on opposite sides of the World but surely when the sun and the Moon are together they Combined gravities pull Harder. .Nev

[Litespeed]

Yes, much higher when Sun and moon are on same side.

 

It's called a king tide.

[pmccarthy]

There is a theory about earthquakes and rockfalls and the phase of the moon. I suspect that statistics don't support it.

[onetrack]

I've always believed that earthquakes are associated with strong storms with intense winds and heavy rain. The rainfall often lubricates fault lines, and if they're already under tectonic strain, the lubricating and weight effect of heavy rain will often trigger earthquakes. I'm convinced we're due for a decent earthquake again in Australia, they usually come about every 60 years.

[willedoo]

onetrack, are you typing that with your mudboots on? I've been looking at the weather over there.

[facthunter]

Why not PMC? You purport to be a geologist and the Oblate spheroidal shape of the Earth is due to the earth spinning, then why wouldn't the Sun and Moons gravity affect the surface of the earth which is only about 40 miles thick? Tensions build up in the crust and changes can trigger movement. That's why you get aftershocks. Underground Mining magnifies the effects like the Earthquakes in Newcastle at the end of the  80's,  45 years ago. People died then from quite a mild tremor. Nev

[rgmwa]

Nev, the Newcastle earthquake was a lot more severe than quite a mild tremor. It was a magnitude 5.6 event. Meckering in WA was 6.5 and Australia's strongest ever recorded earthquake was 6.6 at Tennant Creek. Granted that on a log scale, 5.6 represents a lot less energy than 6.6, but Newcastle was a significant event and Australia's most costly in terms of property damage. It killed 13 people, hospitalised 160 and damaged over 35,000 homes, 147 schools and 3000 commercial buildings and cost about $4b. It also led to the Earthquake Design Code being substantially overhauled to make buildings more resilient.

Unlike other types of loads such as wind (including cyclones), and live load where the aim is to prevent any significant damage in a worst case event, the aim in earthquake design is to prevent loss of life, not to prevent damage to the structure. The aim is to have the structure fail in a predicable way but hold together long enough to allow people to get out. The structure may well be uninhabitable after the event and need to be demolished.

 

Edited 1 hour ago by rgmwa

[facthunter]

The extent of the damage was related to the Undermining of the Most Affected areas and the Proximity to the surface of the extracted coal  Most Had the Plllar coal removed and was water filled. I think the scale IS NOT LINEAR as you also say. I'm FROM Newcastle so I'm aware of the Nature of the damage. Newcastle experiences a lot of subsidence damage without any seismic activity. Recently there has Been seismic activity west of there. I wouldn't suggest the Area is Particularly prone to earthquakes. We have had a few shakes Here Near Mt Macedon with the Epicentre maybe 100 Kms east. Nev

[willedoo]

I knew a lot of bricklayers that went to Newcastle for the reconstruction work. One of them told me that a lot of the cavity brick walls that fell down had almost no wire brick ties left due to rusting away in the salt air environment. Whole sections of walls weren't tied together. 

[rgmwa]

Yes, that led to the much more widespread use of stainless steel brick ties in coastal areas. 

This is a map of the earthquake hazard areas in Australia. The closer contours highlight the more earthquake prone areas. By and large Australia is a pretty stable landmass compared to many overseas places, but we still have a number of significant hot spots.

 

Edited 54 minutes ago by rgmwa

[onetrack]

Willie, the storm had little effect on me. We ended up with a fair amount of vegetation trash, the big Jacaranda in our backyard lost a small branch, and the fruit trees took a pounding - but there wasn't a huge amount of rain in the storm, we ended up with a whisker over 33mm from Saturday evening to this (Monday) morning.

 

It's a holiday here (W.A. Day) and many people are at home, having cancelled trips and events due to the storm warning, so everyone seems to be out and about now, picking up limbs and leaves and trash.

The low-lying areas and the river estuarine areas are the ones that went under water. The River backed up due to the storm surge, coupled with a king tide, and it put a lot of areas under water that I haven't seen submerged for years.

 

The buildings on the coast take the brunt of any stormy winds, the houses and apartments near the coast always seem to lose parts of roofs when a big storm comes through.

I'm about 6.5kms inland from the coast, as the crow flies, so the winds are moderated by the time they get to my neck of the woods.

 

Edited 32 minutes ago by onetrack