Coastal redwood, Sequoia sempervirens, are remarkable stable trees. They rarely fall, which is how they get to be thousands of years old. They prefer to live in groups, where they mesh their roots together, and shelter each other from wind. Those that live outside of a group stay shorter than forest trees, and typically develop multiple trunks that function as a group.
However, they are also remarkably weak in regard to their structural integrity. Limbs are easily broken away from their vertical trunks by wind. Snow, which is rare within their natural range, causes significantly more damage than wind, which is probably why their natural range does not extend into snowy climates. Trees with co-dominant leaders (double trunks that divide from single trunks above grade) have potential to split at the union of the double trunks. Such unions are typically at such acute angles, that the trunks press against each other rather than fuse together through impenetrable compressed bark.
Leaning redwoods such as these that were shown earlier this morning, are potentially hazardous, not because they are likely to fall over, but because they might be likely to break. The trunks are designed to support weight vertically. The asymmetrical distribution of weight supported by these two trunks exerts inordinate lateral tension on the trunks. To make matters worse, the trunk to the left is divided into two co-dominant leaders, although the union does not appear to be at a typically acute angle. (The lower trunk is now behaving more as a big limb than as a secondary trunk.)
I would guess that these two trees are genetically identical trunks from the same root system. Such seemingly pliable trunk structure is uncommon, and it is very unlikely that two such similar trees would just coincidentally appear within such minimal proximity to each other. Redwoods often develop multiple trunks from the same root system, particularly as they regenerate after harvest.
The good news is that these two trunks have survived like this long enough to develop ‘reaction’ wood, which is just like it sounds; a bit of extra wood to compensate for compression on the inside of the bend. Also, they are sheltered from wind by the other redwood in the forest around them.