Shield volcano are cave-like volcanic straights formed by the hardening of overlaying lava. These structures help further the propagation of lava, as the walls of the tube insulates the lava within. Lava tubes can account for a large portion of shield volcano activity; for example, an estimated 58% of the lava forming Kīlauea comes from lava tubes. In some shield volcano eruptions, basaltic lava pours out of a long fissure instead of a central vent, and shrouds the countryside with a long band of volcanic material in the form of a broad plateau. Plateaus of this type exist in Iceland, Washington, Oregon,
When It Rains, It Pours (30 Rock) at the time of the broadcast. The rating/share was the same number as the previous week's season premiere episode, "The Fabian Strategy"; in the week that "When It Rains, It Pours" originally aired, "30 Rock" was the only Thursday program whose ratings did not fall from its season premiere. In February 2011, Robert Carlock won the Writers Guild of America Award for Episodic Comedy for his work in this episode of "30 Rock". Television columnist Alan Sepiwall for HitFix called this the best overall episode since season four's December 2009 episode "Dealbreakers Talk Show #0001". He wrote that the episode