What happens to the magnetic compass at the magnetic pole?

A magnetic compass needle tries to align itself with the magnetic field lines. However, at (and near) the magnetic poles, the fields of force are vertically converging on the region (the inclination (I) is near 90 degrees and the horizontal intensity (H) is weak). The strength and direction tend to "tilt" the compass needle up or down into the Earth. This causes the needle to "point" in the direction where the compass is tilted regardless of the compass direction, rendering the compass useless.

There are established zones around the north and south magnetic poles where compass behavior is deemed to be "erratic" and "unusable". These zones are defined where H (the horizontal intensity) is between 3000 nT - 6000 nT (erratic zone) and H is less than 3000 nT (unusable zone).

North Magnetic Pole

The Earth's magnetic field is shaped approximately like that of a bar magnet and, like a magnet, it has two magnetic poles, one in the Canadian arctic, referred to as the North Magnetic Pole, and one off the coast of Antarctica, south of Australia, referred to as the South Magnetic Pole. At the North Magnetic Pole the Earth's magnetic field is directed vertically downward relative to the Earth's surface. Consequently, magnetic dip, or inclination is 90°. In addition, the North Magnetic Pole is the eventual destination for a traveller who follows his or her compass needle from anywhere on Earth.

The North Magnetic Pole is slowly drifting across the Canadian Arctic. The Geological Survey of Canada keeps track of this motion by periodically carrying out magnetic surveys to redetermine the Pole's location. The survey indicates position for the Pole and established that it is moving approximately northwest at 40 km per year.

The observed position for 2001 and estimated positions for 2002 to 2005 are given in the table.

Year	Latitude ( °N)	Longitude ( °W)
2001	81.3	110.8
2002	81.6	111.6
2003	82.0	112.4
2004	82.3	113.4
2005	82.7	114.4