WMOD00299

• Title: Physical Structure of Northern Colorado River Basin Cloud Systems
• Date: 9/1/1985
• State: CO
• Weather Modification - Doc Type: Report

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13

Surface observations of ice nuclei concentrations at Climax were also
reported by Hindman (1967). Hindman investigated the relationship
between ice nuclei concentrations at the Climax High Altitude
Observatory and ice crystal concentrations in snowfall during two seeded
and two non-seeded storm events. After making several assumptions
concerning the large scale and microstructure of the storms analyzed, he
concluded that concentrations of ice nuclei and ice crystals were
similar in the non-seeded cases but differed by an order of magnitude in

the seeded cases (ice nuclei higher). Hindman also presented limited

data on the crystal types and accretion characteristics of precipitation

during these two storm events. More deta~led summaries of crystal

habits, sizes and accretion characteristics as well as ice nuclei

observations during the Climax experiments were presented by Grant

(1965), Chappell (1967), and Chappell (1970) and Vardiman (1972).

Vardiman (1972, 1978) also discussed fragmentation as a possible means

of crystal concentration enhancement in Climax cloud systems.

Radar observations of cloud systems during the Climax experiment

were reported by Furman (1967). Furman examined the echo

characteristics of four spring storms with horizontally and vertically

scanning 3 cm radars. He determined that mean cloud tops over the

Climax region during these storms varied from 450-SS0 mb, although cloud

tops occasionally reached the 3S0 mb level. Furman's analysis implied

that the most intense precipitation (strongest echoes) were consistently

located in the vicinity of ridgetop and that propagation of the echo

pattern closely followed the SOO mb velocity vector. His work primarily

emphasized convective periods which could be most readily observed with

the available radar.