Many or some may have heard about recent tragic snowblower incidents, whereat in one of the most recent ones there is an aspect of heroism in father saving his daughters, at the expense of having to be a double amputee.
Perhaps like a number of others, I read the article, but could not visualize how a scenario of a full size human being could be 'sucked in' to a snowblower. So I did some research.
Before going any further, there is a necessary degree of humility. For the sake of illustration, a bit about my background includes awareness of a wide range of technologies, reference for instance products selected and made available with pictures, and brief selling points through ETIS websites. Notwithstanding, putting together in the mind's eye the basic mechanisms of snowblowers and dangerous possible scenarios, may have been tenuously present, especially given when you say snowblower, the thoughts are just blowing snow to the side. Some of what has been learned thus far, I will try to share in easy to understand language, coupled with safety tips in general. In the hopes that during this winter, and those in the future, the possibility of injury can be minimized.

One of the biggest points it is helpful to understand, towards protecting yourself from being injured by snowblowers, is that they come in different sizes. Basically, you have big snowblowers designed to take care of ski resorts, and you have little snowblowers that you can walk behind to clean your personal sidewalk leading to the front door of your house.

Big snowblowers can suck an entire human being up into them. The small personal snowblowers have many incidents that involve a limb, especially of a hand affected. 

The basic operation of snowblowers looks about the same. It is similar to barbed wire, made of steel, a cylindrical or weaving with circular saws type apparatus, that grinds the snow up, then blows it out a shoot. No matter what size, usually there is an aspect of cutting, involved with the snowblowers.

Snowblowers discussed here are distinguished from a simple blower that just blows snow away with a heater and fan combination.

In regard to snowblowers that cut, the rule is about the same, keep a safe distance. Small snowblowers, do not under any circumstance, stick your hand or foot down in there and try to unjam it. Even if it is turned off, the stuck parts are still waiting to finish the rotation the power mechanism already energized it to do, so when it gets unstuck, it may suddenly spin, and could do so with enough force, it could cause serious injury.

For the large snowblowers that someone could sit in a drive like a tractor, it may be suggested to stay far enough away from it, so that if you slip and fall, you do not wind up close enough to it that you end up getting stuck in there, wholly or partially.

Safety when dealing with wheeled vehicles such as trucks and cars, planes, and trains, may be much more familiar that snowblowers. A driver education course taught may not come with the access of using a snowblower. Attention to detail in operating snowblowers safely is still wise.

There are many kinds of injuries that could take place having to do with snowblowers, such as slips and falls, and cardiac arrest. Heart conditions could occur, plausibly, when the combinations of the strain of operating the equipment, along with cold weather, and the vibratory effects, become an imbalance over what a person usually undergoes in activities, such as an afternoon walk, especially in older persons.

Snowblower safety training and awareness being ramped up, may be a sound calling.

Helpful sources:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7781562/
Events Due to Snowblower Use Seen in US Emergency Departments From 2003 Through 2018
Published online 2020 Dec 1

This post is subject to edits, such as adding citations and pictures.