February 14, 2011 Magnetic Disturbance - Peak Dst 30 nT

Science Center Objects

Space Weather Events of February 14, 2011

On February 14 a small magnetic storm occurred, generating a certain amount of interest in the press (e.g., The Washington Post, Feb. 17, 2011). The NOAA Space Weather Prediction Center, having observed a solar flare and a “coronal mass ejection” from an active region in the vicinity of a sunspot on Feb. 15, has forecast a 20% chance for a “minor” storm on Feb. 18. If such a storm occurs, it will be measured by the USGS geomagnetic observatory network, and USGS data will be used by both NOAA and the US Air Force to issue warnings so that mitigating steps can be taken by satellite and power-grid operators (among others). The Feb. 18 storm, if it occurs, can be expected to cause aurora that can be seen at night at high latitudes.

From 2007 to about 2009, the sun was at a minimum in its 11-year cycle of variation. During this time, and as a result, geomagnetic activity was relatively quiescent. Now, however, we are in the midst of the early stages of a new solar cycle (number 24); solar activity, sunspot numbers, and geomagnetic activity have been increasing. We can expect that over the next few years, and especially at solar maximum around the years 2013 and 2014, that several large and potentially hazardous magnetic storms will occur.

Magnetic storms result from the dynamic interaction of the solar wind and the coupled magnetospheric-ionospheric system of the Earth. Large magnetic storms represent a potential hazard for the activities and infrastructure of our modern, technologically based society. The possible effects of a large magnetic storm were the subject of a recent National Research Council report (Baker et al., 2008), which estimated that if a storm the size of the 1859 one were to occur today, damage to technological systems and resulting carry-on economic effects could cost the United States more than $1 trillion. Such storms can cause the loss of radio communication, reduce the accuracy of global-positioning systems, damage satellite electronics and affect satellite operations, increase pipeline corrosion, and induce voltage surges in electric power girds, causing blackouts. Even small storms can sometimes have surprising effects. A “substorm” on April 5, 2010, resulted in the temporary loss of the Galaxy-15 communications satellite that operators are still trying to repair.

Because the practical effects of space weather are realized on, or just above, the surface of the Earth, ground-based sensor systems, including the magnetic observatories of the USGS, play an important role in space-weather monitoring (Love 2008). The intensity of the Feb. 14 event was measured by the USGS storm-time disturbance index, Dst (Gannon et al., 2011), derived from global observatory data, including those collected by the USGS; -Dst had a maximum “main-phase” intensity of 30 nanoTesla (nT). For perspective, the largest storm of the 20th that of March 1989, had a maximum intensity of 525 nT, and the largest magnetic storm ever recorded, that of Sept. 1859, had a maximum intensity of about 1600 nT. While the Feb. 14 storm was quite small, and the Feb. 18 event may not be too much larger, both are reminders of what we can expect in the coming years, and the vital role of the USGS magnetic observatories.

Prepared on Feb. 18, 2011
Edited by Jeffrey J. Love on Sept. 15, 2014
Last Updated 2014-10-06 18:07:28 by Jeffrey J. Love and Jennifer L. Gannon