Fire and Ice: Geology of the Boston Harbor Islands Saturday, Oct. 10, 2020 NSPN Trip Level 3 Note: This trip is at least 12 nautical miles in length, with exposed ocean portions, crossing a busy shipping lane, currents of 1 knot or less, and rocky beach landings. We will not cancel for rain or for moderate-water conditions. Big conditions or storms will cancel, and we will work out an alternate date. We paddle all the time in rocky environments, and the rocks all have a story to tell.