Puget Sound Convergence Zone Puget Sound Convergence Zone The Puget Sound Convergence Zone (PSCZ) is a meteorological phenomenon that occurs over Puget Sound in the U.S. state of Washington. It is formed when the large-scale air flow splits around the Olympic Mountains and then converges over Puget Sound. This convergence zone generally occurs between north Seattle and Everett and can cause updrafts and convection, which leads to a narrow band of precipitation. A second, weaker convergence zone can occur between approximately Victoria, British Columbia, and Bellingham, Washington, over the San Juan Islands, as a result of southwesterly air blowing from the Strait of Juan
Puget Sound faults Lowland. In particular, to the southeast of Mount St. Helens and Mount Rainier they reflect a regional pattern of NNW oriented faulting, including the Entiat Fault in the North Cascades and the Portland Hills and related faults around Portland (see QFFDB fault map). Yet the SHZ and WRZ may be integral to the regional geology of Puget Sound, possibly revealing some deep and significant facets, and may also present significant seismic hazard. The WRZ and SHZ are associated with the "southern Washington Cascades conductor" (SWCC), a formation of enhanced electrical conductivity lying roughly between Riffe Lake and Mounts St. Helens,