  The onset of the "Rush to the Poles" of polar-crown prominences and their
associated coronal emission is a harbinger of solar maximum. Altrock (Solar
Phys. 216, 343, 2003) showed that the "Rush" was well-observed at 1.15 Ro in
the Fe XIV corona at the Sacramento Peak site of the National Solar Observatory
prior to the maxima of Cycles 21 to 23. The data show that solar maximum in
those cycles occurred when the center line of the Rush reached a critical
latitude of 76 +- 2{\deg}. Furthermore, in the previous three cycles solar
maximum occurred when the highest number of Fe XIV emission features per day
(averaged over 365 days and both hemispheres) first reached latitudes 20 +-
1.7{\deg}. Cycle 24 displays an intermittent Rush that is only well-defined in
the northern hemisphere. In 2009 an initial slope of 4.6{\deg}/yr was found in
the north, compared to an average of 9.4 +- 1.7 {\deg}/yr in the previous
cycles. An early fit to the Rush would have reached 76{\deg} at 2014.6.
However, in 2010 the slope increased to 7.5{\deg}/yr (an increase did not occur
in the previous three cycles). Extending that rate to 76 +- 2{\deg} indicates
that the solar maximum in the northern hemisphere already occurred at 2011.6 +-
0.3. In the southern hemisphere the Rush to the Poles, if it exists, is very
poorly defined. A linear fit to several maxima would reach 76{\deg} in the
south at 2014.2. In 1999, persistent Fe XIV coronal emission known as the
"extended solar cycle" appeared near 70{\deg} in the north and began migrating
towards the equator at a rate 40% slower than the previous two solar cycles.
However, in 2009 and 2010 an acceleration occurred. Currently the greatest
number of emission features is at 21{\deg} in the North and 24{\deg}in the
South. This indicates that solar maximum is occurring now in the North but not
yet in the South.
