Montreal, Canada

Since hitting a low last July, the benchmark Reuters-CRB Index of 19 commodities has surged 29%. The widely followed CRB Index is now at its highest level since the credit crisis but remains 29% below its all-time high recorded in July 2008.

Commodities are hot, red hot. You could say we’ve entered the “super-spike” phase over the last six months, triggered by the Fed’s desire to print more currency and grow inflation. Just about everything in the complex has been rocketing since last August.

Other catalysts contributing the super-spike include major flooding in coal-producing Queensland, Australia; the worst crop harvests in decades in several countries and rising inflows from ETFs into new base metal funds and other raw materials.

Grain prices have now gained more than 50% since bottoming earlier last summer and the stakes are growing as governments are forced to control rapidly rising food costs.

Food riots are erupting once again with protests turning violent in Algeria last week. The Chinese and other emerging market governments have their hands full as food prices soar; The Economist’s Food Price Index hit a new high last week and is poised to rise even higher because recent USDA crop forecasts point to sharply lower inventories in 2011. The United States is the world’s largest exporter of grains.

Oil and gas stocks are also on the move. The S&P Oil & Gas Index has rallied more than 54% since last September alone. Agriculture stocks, as measured by the Market Vectors Agribusiness ETF (NYSE-MOO), has bolted 59% since last May. And gold mining stocks are up more than 36% since last spring.

Momentum has taken over from measured optimism. Investors Intelligence surveys point to the highest levels of optimism since December 2007 and the lowest level of bears since mid-2007.

Somewhere along this exuberant road to profits investors will suffer huge losses as a correction unfolds. Investors forget that commodities fall hard when the trend changes. The macroeconomic picture remains highly uncertain and anything can tip optimism into pessimism pretty quickly. Target what you want to buy when prices fall. But don’t lunge after resource stocks now.