The yarn number is the length in yards of one pound of the yarn, divided by 1600. Symbol Nar. This is the same as the weight in ounces of 100 yards. So one pound of number 1 run yarn is 1600 yards long, one pound of number 2 run yarn is 3200 yards long, and so on.
As with most other volcanoes in the Cascade Range, Mount St. Helens is a large eruptive cone consisting of lava rock interlayered with ash, pumice, and other deposits. The mountain includes layers of basalt and andesite through which several domes of dacite lava have erupted.
The most recent volcanic eruption of Mount St. Helens in Washington State, which began in October, 2004, produced hot, but solid, extrusions of smooth-sided lava called spines.. The extrusion of the solid lava spines continued until January 2008, producing more than 120 million cubic yards of solidified lava.