A quick look at the Pine Lake storm

On 14 July 2000, at about 6:45 pm to 7:15 pm MDT, a devasting tornado struck the Pine Lake and hit the Green Acres Trailer Park. Twelve deaths, one hundred and thirty injuries and more than thirteen millions of dollars of damage were reported. The storm was approximately 150km south of the Carvel radar which is located about 40 km north west of Edmonton. The radar performs a 5 minute 24 elevation volume scan and then a 5 minute 4 elevation Doppler scan sequence. The Carvel radar is a 1.1 degrees beamwidth, C Band radar with a maximum range of 256 km when operating in non-Doppler mode, and a range of 113 km in primary Doppler mode and 226 km in ``random phase'' mode. In this latter mode, the phase information of the return pulse is processed with the phase form the current and the previously transmitted pulse to retrieve the first and second trip echoes, respectively. At the moment, it is limited to an unambiguous velocity of 16 m/s. This ``random phase'' scan is a recent technological innovation pioneered for operational use at the King Radar and used on all National Radar Project radars. The Carvel radar was initially Dopplerized in 1991 and upgraded in 2000 to National Radar Project standards. In this quick look we examine the sequence of low-level CAPPI's made at 1.5 km above the ground, several of the radial velcoity images form the random phase can and report on the damage track. CAPPI is an acronym for Constant Altitude Plan Position Indicator. It is a display of a horizontal slice through the three dimensional radar volume.