Old Faithful geyser was scheduled to erupt at 4 p.m., but five minutes later, it was still steaming gently into a clearing sky.

The sign predicting the eruption actually said Old Faithful could go off at any time from 3:40 to 4:20 p.m. Still, a tourist near me looked at his watch and muttered, ?Damn nature.?

But for every pessimist there?s an optimist. The pessimists doubt that, but the optimists hope it?s true.

Anyway, Old Faithful went off at 4:10 p.m., with one of the puniest eruptions I?d ever seen.

Its first burst reached only half of the geyser?s 130-foot-high potential, and the eruption quickly settled down to a 20-30-foot-high spout. Less than two minutes later, it was all over.

I?ve seen Old Faithful go twice as high for twice as long, so I was thinking, ?What was that all about??

The woman next to me, however, was wonderstuck. ?I?ve never seen the earth do that before,? she exclaimed.

The difference between us was that I?d seen Old Faithful erupt many times. This was a first for her.

That?s why I decided to make Old Faithful one of the last stops on my fall tour of Yellowstone. I had only one day in the park while picking up my son from his summer job, and I was determined to see most of the pools and geysers I?d never seen before.

After visiting the Fountain Paint Pots, or Lower, Geyser Basin, I left the Grand Loop road for the two-mile Firehole Lake Drive loop.

Firehole Lake is one of the park?s largest hot pools. Boiling water flows from a large pool under a bridge to a second pool, then flows down the Hot Cascades to an even larger lake. Small geysers play inside the edges of the pools.

Nearby is the Great Fountain geyser, which can erupt in 100- foot to 230-foot-high bursts for 50-75 minutes. Unfortunately, the interval between eruptions is seven to 15 hours, and I arrived at the midpoint.

I also missed the eruption of White Dome geyser. Its tall cone dominates the landscape like a miniature white volcano.

I may have missed the main eruptions, but at least I enjoyed perfect weather on my drive around Firehole Lake. I would spend the rest of the day running from thunderstorms.

Threatening clouds were gathering above me by the time I reached Midway Geyser Basin, but I figured I could walk it quickly and eat lunch in the car when it rained.

Tourists have to cross a pedestrian bridge over the Firehole River to reach the pools and geysers.

It provides an excellent vantage point to observe the runoff from pools and geysers flowing into the river.

Excelsior Geyser alone pours 5 million gallons of hot water a day into the river. The geyser is now a hot pool, 200 feet across.

In the 1880s, however, it used to erupt to heights of 300 feet. Its last eruption, in 1985, lasted for 46 hours.

Grand Prismatic spring is even larger, 370 feet across. It?s known for its intense colors, ranging from blue to orange, green and brown.

Unfortunately, on this cloudy day, all the hot springs were gray. Cold rain began to sprinkle into the mirror-like surface of the pool.

I expected some kind of sizzling interaction, but it looked like rain hitting any pond anywhere.

I returned to my car and split a box of Cheez-its with a couple of gigantic ravens. I knew I wasn?t supposed to feed the wildlife, but these two, Heckle and Jeckle probably, were expert beggars.

I eventually drew a crowd of about 10 ravens, but my two buddies got most of the Cheez-its. I saved the chocolate-chip cookies for myself.

The rain was intermittent, and I wasn?t ready to give up yet. My next stop was Biscuit Basin, which I wisely tackled with umbrella and rain hood.

Unfortunately, Sapphire Pool, Silver Globe, and Mustard Spring were all gray. I hadn?t realized the role the sun plays in Yellowstone. Without light, prisms are nothing.

At least I had the satisfaction of strolling back to my car comfortably under my umbrella, while tourists in shorts and T-shirts ran past me, desperately trying to escape the mountain cloudburst.

I drove through an evil downpour to Black Sand Basin. The windshield wipers, even on high, accomplished little.

Because Yellowstone is natural, you never know what you?re going to experience there. I was looking for shimmering pools, but Green spring, Rainbow pool and Emerald pool were all dead and gray. Even the geysers weren?t doing much.

Yellowstone, as usual, handed me the unexpected. Black Sand Basin is bordered by magnificent sheer cliffs, part of the rim of the caldera that spans the entire south half of the park.

Nature chose that moment to loose all its fury, and the cracks of thunder echoing off the cliff were terrifying and thrilling.

I realized that standing out in a lightning storm while holding onto a metal umbrella wasn?t the brightest thing to do, but I couldn?t tear myself away from the show.

I finally arrived, soaking wet, at Old Faithful and the Upper Geyser Basin. The Old Faithful complex, with an overpass, three lodges, several stores and a visitors? center, is the least natural part of the park.

It?s a bit like Rodeo Drive plopped down into the middle of a pristine forest, but a series of boardwalks takes tourists from the congestion to the heaviest concentration of thermal features anywhere.

Five of the most spectacular geysers in the park are right here: Old Faithful, Riverside, Castle, Daisy and Grand.

During my 1995 visit, each one was ready to go off just as I happened by. This time, nothing.

Signs said Castle geyser had gotten completely out of phase and was now unpredictable. It was steaming nonstop when I walked by.

I crossed the Firehole River and took the boardwalk up Geyser Hill, but most of the small geysers there were also quiet.

Sawmill geyser was the lone exception, sputtering away with the sound of its namesake. At least the sky was clearing and the pools looked better.

By that time, I?d walked several miles during the day, and was too tired to make the long trek down to the famous Morning Glory pool.

I saw it in 1995, however, and was shocked by its decline. When I was a child, the pool was a deep, shimmering blue.

Thanks to years of vandalism, the pool?s thermal vent has become clogged. The water has cooled somewhat, allowing bacteria to turn the rim of the pool a muddy yellow.

Tourists illegally throw coins in all the pools, which disturbs water circulation. Because of its fame, Morning Glory has had trash, rocks and logs thrown into it. I believe rangers had to drag a sofa out of it one time.

Humans may have hastened the demise of some thermal features, but even in nature, geysers stop spouting and pools cool off and dry up. New ones are always springing up somewhere in the park.

The afternoon was wearing on, and I still had a 38-mile drive to reach Lake Village on Yellowstone Lake, where I was supposed to meet my son for dinner.

On the park?s twisty, congested road, that translated to a drive of at least an hour and a half.

I was done with geysers for this trip, but a lot of Yellowstone, and the Grand Tetons, lay ahead.