These wx events should really not come as a surprise, The BOM and Severe Storms Research have both published reports and advisories detailing the dangers of the Darling Scarp. Perth has historically seen dangerous conditions develop in the form of rotor streams when strong low-level easterly flows prevail. Perth, Jandakot and Pearce can be subject to large reversals over very short distances. When synoptics suggest a strong easterly flow, areas west of the Darling scarp may be subjected to exceptional gusts.
BOM info can be found here
http://www.bom.gov.au/aviation/data/...-flying-sw.pdf
The SSR site is presently down but I will provide a link once available.
Regards