The main exodus from Nauvoo began on February 4, 1846 with an advance party under Brigham Young. Archibald Newell Hood and his brother, Alexander Hill, were part of this advance party. The plan was to make it to Utah and establish a colony to receive the main body that would arrive later in the year. Here’s the description of what happened from the Wikipedia article on The Mormon Trail.
This early departure exposed them to the elements in the worst of winter. After crossing the Mississippi River, the journey across Iowa Territory followed primitive territorial roads and Native American trails. Young originally planned to lead an express company of about 300 men to the Great Basin during the summer of 1846. He believed they could cross Iowa and reach the Missouri River in four to six weeks. The actual trip across Iowa was slowed by rain, mud, swollen rivers, poor preparation, and required sixteen weeks – nearly three times longer than planned. Heavy rains turned the rolling plains of southern Iowa into a quagmire of axle-deep mud. Furthermore, few people carried adequate provisions for the trip. The weather, general unpreparedness, and lack of experience in moving such a large group of people all contributed to the difficulties they endured. The initial party reached the Missouri River on June 14. It was apparent that the Latter-day Saints could not make it to the Great Basin that season and would have to winter on the Missouri River.Archibald Hill returned to Nauvoo and brought his family out to Winter Quarters. They arrived in early autumn. Presumably the advance party had already built houses and planted crops in preparation for winter.
Some of the emigrants established a settlement called Kanesville on the Iowa side of the river. Others moved across the river into the area of present-day Omaha, Nebraska, building a camp called Winter Quarters.
Isabella Hood Hill was 25 years old. Samuel Hood Hill was six, Hannah Hood Hill was four, and Rebeccah Hood Hill was only one year old.
About 1000 settlers died that winter of illness or starvation. One of them was Isabella Hood Hill. She died on March 20, 1847 and she is buried in the Mormon Cemetery in Florence, Nebraska [grave #109].
Here, in Hannah Hood Hill’s own words is what happened.
I haven't many pleasant remembrances of my childhood days, for while in Winter Quarters my mother took sick and died, owing to exposure and hardships. This was my first great sorrow. Father left his children; my brother Samuel with his father and mother, my sister Rebecca with one sister, and I with another, and he started with the pioneers to find a home in the west. My aunt moved to a place called Honey Creek, a short distance from Winter Quarters, where my uncle built a log cabin and also cleared some land to plant a crop. While there I remember getting lost in the woods. I started out with my uncle's dinner, saw a little squirrel and thought I could catch him. It led me a chase and I couldn't find my way. I started to cry and called for my uncle. He happened to hear me so told me to stand still, but I was very badly frightened. I didn't get the squirrel. My brother and two cousins and I used to have nice times together, gathering flowers and different kinds of berries and nuts. One day I was sent to the spring for water a mile away from where we lived. When I got there I saw a snake sunning itself by the spring. I would not go near it to get the water so had to wait until it left. Snakes were very plentiful in that part of the country. We lived there about two years, then my father sent for me to come to Salt Lake Valley, in the year 1849. I was very excited and thought we were going on a pleasure trip, but found it was a very long, hard one before we got to the end of our journey. The first night I started out with strangers; they cut off all my hair. I traveled bare-footed and bare-headed; sometimes we would travel two or three days without water. My father met us in Emigration Canyon with vegetables and melons which we enjoyed very much. When we arrived in the valley my father had built a home in the Eighth Ward, where I lived with another aunt, father's oldest sisterHannah’s father had gone on to Utah with the advance party during the summer of 1847. Hannah stayed in the area around Winter Quarters for another two years living with her aunt. She finally arrived in Utah in 1849 when she was seven years old. Most of the remaining members of the extended Hill family also reached Utah in 1849. Her grandparents and her bother Samuel arrived in 1951. Archibald and his children first lived in the fort on the site of present-day Salt Lake City. Later on they moved outside the fort to the rapidly expanding town. He took four wives before he died in Salt lake City on Jan. 2, 1900.