Vietnam will be hit by between 20-25 magnetic storms with an intensity of 150-200nT (nano-teslsa), a unit of magnetic density, in 2011, say the Institute of Geophysics, part of Vietnam’s Academy of Science and Technology.

The magnetic storms are also likely to become more frequent and stronger at the end of the year, the Institute added.

According to Ha Duyen Chau, a senior researcher at the Institute, the earth was hit by a magnetic storm with an intensity of about 60 nT earlier this year.

"It is difficult to predict exactly when a magnetic storm will occur,” said the researcher.
Vietnam first started to study magnetic storms in 1957 but monitoring stations were not installed until after the 500KV national grid began operating in 1998.

Magnetic or geomagnetic storms are caused by changes to the earth’s magnetic field, usually associated with charged particles generated from solar flares and sunspots.

On average they last from between 24 to 48 hours, but some are known to have lasted for many days./.