Extremeweatherguy wrote:Cyclonecarl - - - keep in mind that a Cat. 5 cyclone in Australia is not the same thing as a Cat. 5 hurricane in America. For example, Cyclone Larry actually would have only been a high end Cat. 4 storm in America. (It also seems like Australia bases their storms on gusts),
The experience I wrote of above was Cat 5 TC Joan at Port Hedland, NW Western Australia, in Dec. 1975, which compared to Larry was a much larger and slower moving system, so it was potentially far more destructive (however buildings in NW WA are constructed with monster TC's in mind!).
From the BoM report, Dvorak (1973, 1975) analysis of the final NOAA 4 vis satellite image prior to landfall captured at 08:26 AWST = 00:26 UTC on Dec 7 1975 yielded 915 mb and 10-min 228 km/hr [142 mph, 123 knots] - which translates to max gusts (mean + 40%) of 319 km/hr [198 mph, 172 knots], bearing in mind that satellite images were not as good as today, and Dvorak is not that precise.
By landfall it had probably weakened a little (BoM estimates about 925 to 930 mb), and it crossed the coast about 45km west of us at about 06:00 AWST Dec 8 = 22:00 UTC Dec 7.
TC Joan 1975 BoM report wrote:Wind data recorded at the Nelson Point port site at Port Hedland by an anemometer owned by the Mount Newman Mining Co. Pty Ltd, suggest that a mean wind in excess of 160 km/h probably occurred between 0500 and 0515 8 December. (Unfortunately the anemometer was not capable of actually recording speeds greater than about 155 km/h, but this observation is consistent with the wind recording at the Port Hedland Airport Meteorological Office.)...
...Considering Shea and Gray's (1973) statistical relationship between radar observed precipitation patterns and the maximum wind field in tropical cyclones, it could be inferred from radar photographs of cyclone Joan that the most destructive winds were in a band lying between 25 and 40 km from the centre of the eye. This implies that Port Hedland experienced winds somewhat less than the maximum generated by Joan. The anemometer at the Port Hedland Airport Meteorological Office [edit to add: nearer South Hedland and about 10 km or so inland], which recorded a maximum gust of 208 km/h and a maximum mean (10 minute) wind of 141 km/h, was located 51 km from the centre of Joan at or shortly after landfall.
For those who may be interested, I scanned the BoM report, OCR'd what I could (and I just noticed there are some OCR typo's that need to be corrected!), and put the resulting text and images online
here - note that the senior BoM staff member that sent me the report said it was OK to put it online if I wanted to.
Extremeweatherguy wrote:either way that was an amazing story of what you had to go through in your home. That would freak me out for sure.
Fortunately, in that experience it was not my home but a unit in beachfront motel I was staying in - however it's location on top of a sand dune meant we were exposed to the full brunt of the winds coming in off the ocean, and from looking at the damage around the town afterwards I think the area along the beachfront was probably hit the hardest, although most of the town suffered considerable damage.