Analyzing Word Choice in a Narrative

Read the following excerpt from a fictional narrative:

"As the storm raged outside, the old house creaked and groaned,
its walls echoing the sounds of tempestuous winds.
In the flickering candlelight, she clutched the book to her chest, her heart racing with every thunderous clap that shook the windows."

In this passage, what is the effect of the author’s choice of the word clutched instead of a more casual term?