It would appear that once again water security is back in the news. We either don’t have enough, or in the case of the Canadians, there is far too much…and all at once. Over the past week devastating mud and landslides have wreaked havoc in the Canadian province of British Columbia, costing several lives and millions of dollars in damages. Government geologists came under fire by restricting the access of emergency services to the area due to the instability of the ground underfoot, fearing further slides. Earlier in the week 500 campers were stranded in the Kootenays as they were cut off by mud, rock, broken trees and debris that has been dislodged by the snow melt that continues with persistent warm weather across the province.
In other hydrological news, a 1500 year record of precipitation patterns in North America was published this week in the Proceedings of the National Academy of Sciences. The authors use oxygen isotopes in lake sediments and a physical model to infer changes in rainfall, with findings that are discordant with what has previously been understood from the tree ring record.
This research helps to inform our understanding of drought regimes in North America on centennial/millennial timescales.The authors demonstrate that the Pacific Northwest experienced exceptionally wet conditions during the Medieval Warm Period (900-1300 AD) and much drier conditions during the Little Ice Age (1450-1850 AD) which is in direct contrast to what has been shown to have occurred in the Southwest. The findings have been related to the climate dynamics associated with the Southern Oscillation Index (SOI) the Pacific Decadal Oscillation(PDO). As is often the subject in this blog, these records of past climate help to inform our understanding of what we can expect, and perhaps even predict from our current climate. And in North America the hydrological cycle is an increasingly topical issue, with not enough water in the south, and a little too much in the north.