I have been thinking a lot about ballhootin' lately.

Along the steep slopes of the southern Appalachian Mountains, folks have a word for that sickening oh-my-gosh-how's-this-going-to-end sensation when your car starts sliding down an icy mountain road. It's called ballhootin', and it is a great word. It expresses both the giddy excitement and grim inevitability of an uncertain outcome beyond human control.

The colorful regionalism comes from the area's lumbering days when trees cut high up the side of a mountain would be trimmed of protruding branches, their business ends rounded and, once winter delivered frozen ground and a lubricating blanket of snow, the logs would be sent down the mountain as lumbermen shouted out, "Ballhootin'!" as a warning to those below.

And it's been a ballhootin' market. To recap: During the week of the anniversary of 9/11, hurricanes tore up Texas, Florida and the Caribbean, North Korea sent missiles flying over Japan, President Donald Trump cozied up to his new best buds — "Chuck and Nancy," Democratic congressional leaders Sen. Chuck Schumer and Rep. Nancy Pelosi — and revelations about Russian sponsored anti-Hillary Clinton ads on Facebook fueled more speculation about possible Trump campaign collusion.

During this bone-jarring spate of headlines, the stock market capped its biggest one-week gain of the year, setting new highs along the way. Commentators were quick to explain that the market, in its wisdom, is looking through it all.

Staggering storm losses? Could have been worse. Threats of nuclear war? We will muddle through. Political whiplash and uncertainty at home? We have come to expect the unexpected.

Not everyone is so sanguine, however.

"There's all kinds of reasons for the market to be very jittery, but it's not. So why is that?" asked Tim Quast, a market observer out of Denver. Quast's firm, Modern IR, of which he founded and is its president, pioneered a way to quantify the "behavior of money" behind stock trading, helping public companies understand market gyrations affecting their stocks. "We have a market today where great bulk of money is following a model and tracking a benchmark," he argues.

The market "doesn't react to uncertainty the way it did historically," for two reasons, he said, the predominance of passive investing and the growth of high frequency trading.

Over the last two decades, actively managed funds have steadily lost ground to passive investments. Index funds and ETFs (exchange-traded funds) have grown from 10 percent to 45 percent of investment assets, according to Morningstar Research, and the majority of "new" money coming into the market also goes to these vehicles. In 2008 approximately $500 billion was held in U.S.-based ETFs, which make up the majority of the global ETF market.

That mushroomed to more than $2.5 trillion last year, according to industry data from the Investment Company Institute as investors took money out of actively managed funds. Pointing to the three largest managers who hold almost half of all ETF assets, Quast observes that "BlackRock, Vanguard and State Street will continue to deploy the money we all pump into our target date retirement accounts, and we're not changing in response to this news item or that one."

Target date funds, matching an investor's planned retirement horizon, continually rebalance between domestic and foreign stocks and bonds. These passive vehicles ignore fundamentals, focusing on specific indexes such and the S&P 500 or the Russell 2000, and concentrate their investments "on the same 750 stocks," Quast said.

Add to that the phenomenon of high-frequency traders, who now account for half the daily volume in stocks, much of it trading those same ETFs as they chase every little tick point during the day, but sell entirely out of the market overnight.

The market used to be a barometer of how the majority of investors felt about the economy, risk and uncertainty, but no more Quast argues. Today we have a market "not behaving in a rational fashion the way money used to" he said. "Structure trumps story."

The real risk under the current structure is that ordinary investors will get spooked and stop automatically pouring their 401(k) savings into these passive investments that are fueling the market, he says. This increasing focus on passive investment also potentially opens up the field for skilled active managers who must earn their fees by outperforming the index over the long run.

So what does all of this have to do with your investment portfolio?

Quast reminds investors of the advice financial advisers give to "look through" the noise and focus on their long term financial objectives.

Remember that, the next time the market comes ballhootin' at you.

Brad Allen is a freelance journalist and former investor relations executive for companies including Imation Corp. and Cray Research. His e-mail is brad@bdallen.com.