It was the mother of all rallies today, as the indices exploded in the afternoon after backing and filling all day, holding support. The indices took off in mid-afternoon and rallied strongly into the close, with as strong a thrust as we've ever seen.

The Dow exploded to over 900 at one point, closing up 889 on the day. The S&P 500 ran from 860 to 940, 80 points in the last 2 hours, closing up 91 1/2. And the NDX ran from 1190 to 1290, more than 100 points actually, closing up almost 128. The Philadelphia Semiconductor Index (SOXX) jumped nearly 20 and gained around 9% today.

It was as good as it gets with the indices closing at the highs for the day with a strong thrust particularly in the last 15-20 minutes.

The technicals were very positive by 4 to 1 on advance-declines were on New York and 2 1/2 to 1 on Nasdaq. Up/down volume was 20 to 1 positive on New York on total volume of just under 1 3/4 billion. Nasdaq traded about 3 billion today and had a ratio of about 7 to 1 positive on advancing over declining volume.

TheTechTrader.com board, needless to say, had a monster session, and many stocks exploded in the last hour. Leading the way was CF Industries (CF), on a terrific earnings report, exploded nearly 9 points to close at 54.60. Apple (AAPL) late in the session exploded to near 100, closing at 99.91, up 7.82. Potash (POT) jumped from 61 to 70 and closed at 69.68, up 5.80.

Other stocks of note, Mosaic (MOS) at 29.98 was up 3.48, Focus Media (FMCN) at 14.98 up 2.77, Agrium (AGU) at 30.58 up 3 1/4, and ANR at 29.20 up 3.10.

The ETFs we recommended yesterday had a stellar session, with the DIG finishing at 30.44 up 5.69. EWZ, the Brazilian ETF, at 33.58 was up 4.59, and FXI, the Chinese ETF, at 23.31 was up 3.89. The QLD at 32.54 was up 5.63 today.

There were very few losers today except for the short instruments. The SDS closed at 90.20, down 24.11. The QID, at 68.85, was down 18.95. And they're lower in the aftermarket.

So it was a very significant technical session with the indices exploding into the close, as the shorts got squeezed, big time. The key to today's action was a technical breakout out of a 3-day base and across a couple layers of resistance and across declining tops lines as well, now reaching next key resistance on the hourly charts up near 1300 on the NDX and near the 950 zone the S&P 500.

They'll probably be tested early tomorrow. Today was a very significant session and with any strongl follow-through the bottom may be in.

Harry Boxer is a technical consultant to many Wall Street hedge funds and large institutional traders, and author of TheTechTrader.com, a real-time diary of his day, swing and intermediate-term trades. For more of Harry Boxer, sign up for a free 15-day trial to his Real-Time Technical Trading Diary, or sign up for a free 30-day trial to his Top Charts of the Week service.